Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			$ (162,258)
Other comprehensive income before reclassifications			14,731
Amounts reclassified from accumulated other comprehensive income (loss)			7,393
Total other comprehensive income (loss)	14,762	3,722	22,124	(6,478)
Balance at the end of the period	(140,134)		(140,134)
Pension and other postretirement plans
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			(165,150)
Amounts reclassified from accumulated other comprehensive income (loss)			7,017
Total other comprehensive income (loss)			7,017
Balance at the end of the period	(158,133)		(158,133)
Unrealized gain/(loss) on hedges
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			(1,679)
Other comprehensive income before reclassifications			1,303
Amounts reclassified from accumulated other comprehensive income (loss)			376
Total other comprehensive income (loss)			1,679
Foreign currency translation adjustment
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period			4,571
Other comprehensive income before reclassifications			13,428
Total other comprehensive income (loss)			13,428
Balance at the end of the period	$ 17,999		$ 17,999