Changes in Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 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			(38,100)	(59,503)
Amounts reclassified from accumulated other comprehensive income (loss) to the consolidated statements of income			8,423	6,181
Net current-period other comprehensive income (loss)	$ (19,304)	$ (37,852)	(29,677)	(53,322)
Accumulated other comprehensive income (loss)	(129,130)	(27,378)	(129,130)	(27,378)
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			(665)	(585)
Amounts reclassified from accumulated other comprehensive income (loss) to the consolidated statements of income			792	618
Net current-period other comprehensive income (loss)			127	33
Accumulated other comprehensive income (loss)	(605)	(486)	(605)	(486)
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			1,412	(7,081)
Amounts reclassified from accumulated other comprehensive income (loss) to the consolidated statements of income			7,631	5,563
Net current-period other comprehensive income (loss)			9,043	(1,518)
Accumulated other comprehensive income (loss)	(106,246)	(74,791)	(106,246)	(74,791)
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			(38,847)	(51,837)
Amounts reclassified from accumulated other comprehensive income (loss) to the consolidated statements of income			0	0
Net current-period other comprehensive income (loss)			(38,847)	(51,837)
Accumulated other comprehensive income (loss)	$ (22,279)	$ 47,899	$ (22,279)	$ 47,899