Changes in Accumulated Other Comprehensive Income by Component (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 by Component [Roll Forward]
Accumulated other comprehensive income (loss)			$ (99,453)	$ 25,944
Other comprehensive (loss) income before reclassifications to consolidated statements of income			(16,019)	(19,513)
Amounts reclassified from accumulated other comprehensive income to the consolidated statements of income			5,646	4,043
Net current-period other comprehensive loss	$ 25,611	$ (3,625)	(10,373)	(15,470)
Accumulated other comprehensive income (loss)	(109,826)	10,474	(109,826)	10,474
Gains and Losses on Cash Flow Hedges
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Accumulated other comprehensive income (loss)			(732)	(519)
Other comprehensive (loss) income before reclassifications to consolidated statements of income			(249)	(820)
Amounts reclassified from accumulated other comprehensive income to the consolidated statements of income			550	291
Net current-period other comprehensive loss			301	(529)
Accumulated other comprehensive income (loss)	(431)	(1,048)	(431)	(1,048)
Pension and Other Postretirement Benefit Items
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Accumulated other comprehensive income (loss)			(115,289)	(73,273)
Other comprehensive (loss) income before reclassifications to consolidated statements of income			355	(8,133)
Amounts reclassified from accumulated other comprehensive income to the consolidated statements of income			5,096	3,752
Net current-period other comprehensive loss			5,451	(4,381)
Accumulated other comprehensive income (loss)	(109,838)	(77,654)	(109,838)	(77,654)
Foreign Currency Items
Changes in Accumulated Other Comprehensive Income by Component [Roll Forward]
Accumulated other comprehensive income (loss)			16,568	99,736
Other comprehensive (loss) income before reclassifications to consolidated statements of income			(16,125)	(10,560)
Amounts reclassified from accumulated other comprehensive income to the consolidated statements of income			0	0
Net current-period other comprehensive loss			(16,125)	(10,560)
Accumulated other comprehensive income (loss)	$ 443	$ 89,176	$ 443	$ 89,176