Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at the beginning of the period	$ (25,609,000)
Balance at the beginning of the period, tax	18,998,000
Other comprehensive income (loss) before reclassifications	(3,047,000)
Amount reclassified from accumulated other comprehensive income (loss)
Amortization of prior service credit, net of tax	(12,000)
Amortization of prior service credit, tax	10,000
Amortization of actuarial losses, net of tax	495,000
Amortization of actuarial losses, tax	267,000
Net current-period other comprehensive income (loss)	(2,564,000)
Balance at the end of the period	(28,173,000)
Balance at the end of the period, tax	18,741,000
Pension and Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at the beginning of the period	(30,385,000)
Amount reclassified from accumulated other comprehensive income (loss)
Amortization of prior service credit, net of tax	(12,000)
Amortization of actuarial losses, net of tax	495,000
Net current-period other comprehensive income (loss)	483,000
Balance at the end of the period	(29,902,000)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at the beginning of the period	4,776,000
Other comprehensive income (loss) before reclassifications	(3,047,000)
Amount reclassified from accumulated other comprehensive income (loss)
Net current-period other comprehensive income (loss)	(3,047,000)
Balance at the end of the period	$ 1,729,000