Subordinated Notes (Details) (USD $) In Thousands, unless otherwise specified
|
12 Months Ended |
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
$ 312,894
|
|
Subordinated Debt |
1,197,091
|
1,503,368
|
Subordinated Notes Due 2013 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
49,892
|
49,482
|
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 |
350,656
|
344,347
|
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
|
111,816
|
Debt Instrument, Interest Rate, Effective Percentage |
1.01%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2027
|
|
Junior Subordinated Debentures Due 2028 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
54,593
|
54,593
|
Debt Instrument, Interest Rate, Effective Percentage |
0.93%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2028
|
|
Junior Subordinated Debentures Due 2029 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
23,192
|
Junior Subordinated Debentures Due 2030 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
64,194
|
Junior Subordinated Debentures Due 2033 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
30,929
|
Junior Subordinated Debentures Due 2033 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
6,186
|
Junior Subordinated Debentures Due 2036 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
72,165
|
72,165
|
Debt Instrument, Interest Rate, Effective Percentage |
1.71%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2036
|
|
Junior Subordinated Debentures Due 2036 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
74,320
|
77,320
|
Debt Instrument, Interest Rate, Effective Percentage |
1.76%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2036
|
|
Junior Subordinated Debentures Due 2067 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
114,101
|
Subordinated Notes Due 2012 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
0
|
64,959
|
Subordinated Notes Due 2014 [Member]
|
|
|
Debt Instrument [Line Items] |
|
|
Debt Instrument, Carrying Amount |
130,186
|
134,225
|
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 |
110,321
|
111,953
|
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 |
150,219
|
151,444
|
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 |
$ 92,923
|
$ 92,462
|
Debt Instrument, Interest Rate, Effective Percentage |
5.45%
|
|
Debt Instrument, Maturity Date |
Dec. 31,
2019
|
|