Subordinated Notes (Details) (USD $) In Thousands, unless otherwise specified
|
12 Months Ended |
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
$ 554,496
|
|
Subordinated Debt |
1,503,368
|
1,497,216
|
Subordinated Notes Due 2013 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
49,482
|
49,095
|
Debt Instrument, Interest Rate, Effective Percentage |
6.21%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2013
|
|
Subordinated Notes Due 2020 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
344,347
|
308,289
|
Debt Instrument, Interest Rate, Effective Percentage |
7.00%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2020
|
|
Junior Subordianted Debentures Due 2027 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
111,816
|
138,816
|
Debt Instrument, Interest Rate, Effective Percentage |
1.13%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2027
|
|
Junior Subordinated Debentures Due 2028 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
54,593
|
60,093
|
Debt Instrument, Interest Rate, Effective Percentage |
1.17%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2028
|
|
Junior Subordinated Debentures Due 2029 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
23,192
|
23,248
|
Debt Instrument, Interest Rate, Effective Percentage |
8.54%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2029
|
|
Junior Subordinated Debentures Due 2030 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
64,194
|
64,474
|
Debt Instrument, Interest Rate, Effective Percentage |
8.56%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2030
|
|
Junior Subordinated Debentures Due 2033 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
30,929
|
30,929
|
Debt Instrument, Interest Rate, Effective Percentage |
3.34%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2033
|
|
Junior Subordinated Debentures Due 20334 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
6,186
|
6,186
|
Debt Instrument, Interest Rate, Effective Percentage |
3.65%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2033
|
|
Junior Subordinated Debentures Due 2036 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
72,165
|
77,481
|
Debt Instrument, Interest Rate, Effective Percentage |
1.77%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2036
|
|
Junior Subordinated Debentures Due 20365 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
77,320
|
77,482
|
Debt Instrument, Interest Rate, Effective Percentage |
1.77%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2036
|
|
Junior Subordinated Debentures Due 2067 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
114,101
|
114,072
|
Debt Instrument, Interest Rate, Effective Percentage |
6.69%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2067
|
|
Subordinated Notes Due 2012 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
64,959
|
64,909
|
Debt Instrument, Interest Rate, Effective Percentage |
6.21%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2012
|
|
Subordinated Notes Due 2014 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
134,225
|
136,639
|
Debt Instrument, Interest Rate, Effective Percentage |
5.00%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2014
|
|
Subordinated Notes Due 2016 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
111,953
|
112,420
|
Debt Instrument, Interest Rate, Effective Percentage |
5.59%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2016
|
|
Subordinated Notes Due 2018 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
151,444
|
147,071
|
Debt Instrument, Interest Rate, Effective Percentage |
6.67%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2018
|
|
Subordinated Notes Due 2019 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
$ 92,462
|
$ 86,012
|
Debt Instrument, Interest Rate, Effective Percentage |
5.45%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2019
|
|