Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ (218,048)
Other comprehensive loss before reclassifications	(18,325)
Amounts reclassified from accumulated other comprehensive loss	3,699
Total other comprehensive income (loss)	(14,626)	7,362
Balance at the end of the period	(232,674)
Pension and other postretirement benefit plans
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(198,969)
Other comprehensive loss before reclassifications	0
Amounts reclassified from accumulated other comprehensive loss	3,699
Total other comprehensive income (loss)	3,699
Balance at the end of the period	(195,270)
Foreign currency translation adjustment
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(19,079)
Other comprehensive loss before reclassifications	(18,325)
Total other comprehensive income (loss)	(18,325)
Balance at the end of the period	$ (37,404)