Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenue	$ 887,069	$ 839,031	$ 835,886	$ 844,589	$ 936,947	$ 869,541	$ 880,891	$ 890,681	$ 3,406,575	$ 3,578,060	$ 3,821,504
Interest expense									(88,970)	(87,583)	(90,888)
Tax provision (benefit)	38,204	23,197	33,394	37,024	44,204	42,676	52,351	50,547	131,819	189,778	112,815
Net income	(79,079)	$ 70,105	$ 58,184	62,640	90,873	$ 93,876	$ 156,363	85,206	111,850	426,318	352,130
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at				(888,635)				(846,156)	(888,635)	(846,156)	(574,556)
Other comprehensive income (loss) before reclassifications									(77,619)	(73,459)	(297,246)
Amounts reclassified from accumulated other comprehensive income (loss)									26,121	30,980	25,646
Other comprehensive loss									(51,498)	(42,479)	(271,600)
Balance at	(940,133)				(888,635)				(940,133)	(888,635)	(846,156)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at				(3,912)				(4,689)	(3,912)	(4,689)	(6,380)
Other comprehensive income (loss) before reclassifications									1,095	546	1,146
Amounts reclassified from accumulated other comprehensive income (loss)									1,332	231	545
Other comprehensive loss									2,427	777	1,691
Balance at	(1,485)				(3,912)				(1,485)	(3,912)	(4,689)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at				536				2,966	536	2,966	(1,769)
Other comprehensive income (loss) before reclassifications									(1,109)	(1,715)	4,010
Amounts reclassified from accumulated other comprehensive income (loss)									693	(715)	725
Other comprehensive loss									(416)	(2,430)	4,735
Balance at	120				536				120	536	2,966
Pension and postretirement benefit plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at				(738,768)				(786,079)	(738,768)	(786,079)	(601,421)
Other comprehensive income (loss) before reclassifications									(73,141)	19,146	(212,818)
Amounts reclassified from accumulated other comprehensive income (loss)									24,096	28,165	28,160
Other comprehensive loss									(49,045)	47,311	(184,658)
Balance at	(787,813)				(738,768)				(787,813)	(738,768)	(786,079)
Foreign currency adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at				$ (146,491)				$ (58,354)	(146,491)	(58,354)	35,014
Other comprehensive income (loss) before reclassifications									(4,464)	(91,436)	(89,584)
Amounts reclassified from accumulated other comprehensive income (loss)									0	3,299	(3,784)
Other comprehensive loss									(4,464)	(88,137)	(93,368)
Balance at	$ (150,955)				$ (146,491)				(150,955)	(146,491)	(58,354)
Amounts Reclassified from AOCI | Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenue									68	1,082	1,276
Cost of sales									(222)	551	(140)
Interest expense									(2,028)	(2,028)	(2,028)
Total before tax									(2,182)	(395)	(892)
Tax provision (benefit)									(850)	(164)	(347)
Net income									(1,332)	(231)	(545)
Amounts Reclassified from AOCI | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax provision (benefit)									(433)	419	(424)
Net income									(693)	715	(725)
Interest income									(1,126)	1,134	(1,149)
Amounts Reclassified from AOCI | Pension and postretirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total before tax									(38,526)	(44,131)	(43,803)
Tax provision (benefit)									(14,430)	(15,966)	(15,643)
Net income									(24,096)	(28,165)	(28,160)
Transition asset									8	9	10
Prior service costs									(164)	(171)	(111)
Actuarial losses									$ (38,370)	$ (43,969)	$ (43,702)