Pension and Other Postretirement Benefits (Details 9) (Defined benefit pension plans [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 340,370	$ 357,893	$ 325,356
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	120,989	132,032
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	219,381	225,861
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0
Cash and short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,227	4,157
Cash and short-term investments [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,227	4,157
Cash and short-term investments [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Cash and short-term investments [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, U.S. large-cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	86,709	98,766
Equity Securities, U.S. large-cap [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	41,419	50,847
Equity Securities, U.S. large-cap [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	45,290	47,919
Equity Securities, U.S. large-cap [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, U.S. mid-cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	33,264	38,069
Equity Securities, U.S. mid-cap [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	33,264	38,069
Equity Securities, U.S. mid-cap [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, U.S. mid-cap [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, U.S. small-cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	36,079	38,959
Equity Securities, U.S. small-cap [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	36,079	38,959
Equity Securities, U.S. small-cap [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, U.S. small-cap [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	69,163	74,308
Equity Securities, International equities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Equity Securities, International equities [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	69,163	74,308
Equity Securities, International equities [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
U.S. bond funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	61,974	57,547
U.S. bond funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
U.S. bond funds [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	61,974	57,547
U.S. bond funds [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
International bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	27,221	29,313
International bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
International bonds [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	27,221	29,313
International bonds [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Real estate securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	15,432	16,199
Real estate securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Real estate securities [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	15,432	16,199
Real estate securities [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	301	575
Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Other [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	301	575
Other [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 0	$ 0