Quarterly report pursuant to Section 13 or 15(d)

Benefit Plans (Details)

v2.4.0.6
Benefit Plans (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Dec. 31, 2011
Mar. 31, 2012
Pension Benefits [Member]
Mar. 31, 2011
Pension Benefits [Member]
Mar. 31, 2012
Post Retirement Benefits [Member]
Mar. 31, 2011
Post Retirement Benefits [Member]
Components of net periodic benefit expense            
Service cost     $ 6,217 $ 5,413 $ 0 $ 0
Interest cost     7,304 7,518 338 405
Expected return on plan assets     (11,433) (10,823) 0 0
Amortization of transition asset     (1) (1) 0 0
Amortization of prior service cost     (1,442) (1,442) (338) (338)
Amortization of gains (losses)     6,739 5,874 (83) (106)
Settlements     1,750 1,750 0 0
Benefit expense     9,134 8,289 (83) (39)
Change in Benefit Obligation [Roll Forward]            
Service cost     6,217 5,413 0 0
Interest cost     7,304 7,518 338 405
Change in Fair Value of Plan Assets            
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance 579,672 538,970        
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance $ 579,672 $ 538,970