Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			$ (218,048)
Other comprehensive income before reclassifications			3,095
Amounts reclassified from accumulated other comprehensive loss			7,399
Total other comprehensive income	$ 25,120	$ 14,762	10,494	$ 22,124
Balance at the end of the period	(207,554)		(207,554)
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 income before reclassifications			0
Amounts reclassified from accumulated other comprehensive loss			7,399
Total other comprehensive income			7,399
Balance at the end of the period	(191,570)		(191,570)
Foreign currency translation adjustment
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			(19,079)
Other comprehensive income before reclassifications			3,095
Total other comprehensive income			3,095
Balance at the end of the period	$ (15,984)		$ (15,984)