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, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	$ 240,909	$ 224,949	$ 472,976	$ 444,874
Tax (benefit) expense	16,998	19,270	24,983	28,114
Total reclassifications for the period, net of tax	(25,145)	(29,107)	(37,639)	(40,457)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative expenses	4,929	4,334	9,672	8,839
Tax (benefit) expense	(1,918)	(1,687)	(3,763)	(3,439)
Total reclassifications for the period, net of tax	3,011	2,647	5,909	5,400
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	5,361	4,644	10,536	9,453
Tax (benefit) expense	(2,086)	(1,808)	(4,099)	(3,678)
Total reclassifications for the period, net of tax	3,275	2,836	6,437	5,775
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	(432)	(310)	(864)	(614)
Tax (benefit) expense	168	121	336	239
Total reclassifications for the period, net of tax	$ (264)	$ (189)	$ (528)	$ (375)