Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Accelerated Stock Repurchase Program	Common Stock	Common Stock Accelerated Stock Repurchase Program	Additional Paid-in Capital	Additional Paid-in Capital Accelerated Stock Repurchase Program	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Treasury Stock Accelerated Stock Repurchase Program
Beginning Balance at Dec. 31, 2013	$ 2,063,187		$ 544,568		$ 1,432,974		$ 463,843	$ (37,341)	$ (340,857)
Beginning Balance (in shares) at Dec. 31, 2013			192,652
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	157,894						157,894
Other comprehensive income	19,619							19,619
Stock issued, including related tax benefits	8,282		$ 987		1,684				5,611
Stock issued, including related tax benefits (in shares)			781
Stock-based compensation awards	5,865				5,865
Acquisition of treasury stock	(175,255)								(175,255)
Acquisition of treasury stock (in shares)			(14,509)
Deferred accelerated stock repurchase payment	(20,000)				(20,000)
Common stock cash dividends	(62,927)						(62,927)
Ending Balance at Dec. 31, 2014	1,996,665		$ 545,555		1,420,523		558,810	(17,722)	(510,501)
Ending Balance (in shares) at Dec. 31, 2014			178,924
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	149,502						149,502
Other comprehensive income	(4,295)							(4,295)
Stock issued, including related tax benefits	10,808		$ 1,586		4,229				4,993
Stock issued, including related tax benefits (in shares)			1,018
Stock-based compensation awards	5,938	$ 0			5,938	$ 20,000				$ (20,000)
Acquisition of treasury stock	(50,000)								(50,000)
Acquisition of treasury stock (in shares)			(3,976)	(1,790)
Common stock cash dividends	(66,724)						(66,724)
Ending Balance at Dec. 31, 2015	2,041,894		$ 547,141		1,450,690		641,588	(22,017)	(575,508)
Ending Balance (in shares) at Dec. 31, 2015			174,176
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	161,625						161,625
Other comprehensive income	(16,432)							(16,432)
Stock issued, including related tax benefits	17,131		$ 2,566		10,356				4,209
Stock issued, including related tax benefits (in shares)			1,350
Stock-based compensation awards	6,556				6,556
Acquisition of treasury stock	(18,545)								(18,545)
Acquisition of treasury stock (in shares)			(1,486)
Common stock cash dividends	(71,114)						(71,114)
Ending Balance at Dec. 31, 2016	$ 2,121,115		$ 549,707		$ 1,467,602		$ 732,099	$ (38,449)	$ (589,844)
Ending Balance (in shares) at Dec. 31, 2016			174,040