Pension and Other Postretirement Benefits (Details 9) (Defined benefit pension plans [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 387,553	$ 340,370	$ 357,893
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	141,669	120,989
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	244,350	219,381
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,534	0
Cash and short-term investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	14,633	10,227
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	14,633	10,227
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	95,145	86,709
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	43,388	41,419
Equity Securities, U.S. large-cap [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,757	45,290
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	41,090	33,264
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	41,090	33,264
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	42,558	36,079
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	42,558	36,079
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	77,111	69,163
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	77,111	69,163
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	66,276	61,974
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	66,276	61,974
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	29,032	27,221
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	29,032	27,221
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	20,174	15,432
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	20,174	15,432
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	1,534	301
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	0	301
Other [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 1,534	$ 0