Accumulated Other Comprehensive Income (Loss) - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	$ 250,565	$ 240,909	$ 495,297	$ 472,976
Tax (benefit) expense	17,530	16,998	27,672	24,983
Total reclassifications for the period, net of tax	(25,694)	(25,145)	(40,791)	(37,639)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	4,358	4,929	9,058	9,672
Tax (benefit) expense	(1,696)	(1,918)	(3,524)	(3,763)
Total reclassifications for the period, net of tax	2,662	3,011	5,534	5,909
Actuarial Losses Recognized | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	4,786	5,361	9,936	10,536
Tax (benefit) expense	(1,862)	(2,086)	(3,865)	(4,099)
Total reclassifications for the period, net of tax	2,924	3,275	6,071	6,437
Prior Service Costs Recognized | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	(428)	(432)	(878)	(864)
Tax (benefit) expense	166	168	341	336
Total reclassifications for the period, net of tax	$ (262)	$ (264)	$ (537)	$ (528)