Pension and Other Postretirement Benefits - Fair Value Hierarchy - Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 106,900	$ 98,438
Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	44,622	42,259
Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,744	9,019
Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,534	47,160	45,673
Insurance Contract [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,146	46,797	45,334
Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	388	363	339
Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	45,991	43,470	43,103
Domestic [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	45,991	43,470
Domestic [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	44,526	42,056
Domestic [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,465	1,414
Domestic [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Cash and Cash Equivalents [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	905	4,066
Domestic [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	905	4,066
Domestic [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Securities Large Cap [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	12,195	11,260
Domestic [Member] | Equity Securities Large Cap [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	12,195	11,260
Domestic [Member] | Equity Securities Large Cap [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Securities Large Cap [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds Large Cap [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,551	5,629
Domestic [Member] | Equity Funds Large Cap [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,551	5,629
Domestic [Member] | Equity Funds Large Cap [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds Large Cap [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Securities Small Cap [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	539	389
Domestic [Member] | Equity Securities Small Cap [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	539	389
Domestic [Member] | Equity Securities Small Cap [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Securities Small Cap [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds Small Cap [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,910	1,641
Domestic [Member] | Equity Funds Small Cap [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,910	1,641
Domestic [Member] | Equity Funds Small Cap [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds Small Cap [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds International Developed And Emerging Markets [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,107	3,848
Domestic [Member] | Equity Funds International Developed And Emerging Markets [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,107	3,848
Domestic [Member] | Equity Funds International Developed And Emerging Markets [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Funds International Developed And Emerging Markets [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Equity Securities International Developed And Emerging Markets [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,527
Domestic [Member] | Equity Securities International Developed And Emerging Markets [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,527
Domestic [Member] | Equity Securities International Developed And Emerging Markets [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0
Domestic [Member] | Equity Securities International Developed And Emerging Markets [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0
Domestic [Member] | Corporate Debt Securities [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,297	9,480
Domestic [Member] | Corporate Debt Securities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,297	9,480
Domestic [Member] | Corporate Debt Securities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Corporate Debt Securities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Fixed Income Funds [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,483	5,743
Domestic [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,483	5,743
Domestic [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Domestic And Foreign Government Debt Securities [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	12
Domestic [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	12
Domestic [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0
Domestic [Member] | Domestic And Foreign Government Debt Securities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0
Domestic [Member] | Pooled Separate Accounts [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,465	1,414
Domestic [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Domestic [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,465	1,414
Domestic [Member] | Pooled Separate Accounts [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	60,909	54,968	52,873
Foreign [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	60,909	54,968
Foreign [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	96	203
Foreign [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	9,279	7,605
Foreign [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,534	47,160
Foreign [Member] | Cash and Cash Equivalents [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	96	203
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	96	203
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Cash and Cash Equivalents [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Fixed Income Funds [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,207	3,475
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,207	3,475
Foreign [Member] | Fixed Income Funds [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Insurance Contract [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,146	46,797
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Insurance Contract [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	51,146	46,797
Foreign [Member] | Equity Funds Diversified [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	5,072	4,130
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	5,072	4,130
Foreign [Member] | Equity Funds Diversified [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Real Estate Fund [Member] | Total Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	388	363
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0	0
Foreign [Member] | Real Estate Fund [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 388	$ 363