CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2013	$ 2,136,246	$ 932	$ 926,031	$ 1,284,818	$ (72,891)	$ (2,644)
Beginning balance, shares at Dec. 31, 2013		93,236			918
Treasury shares acquired	$ (233,793)				$ (233,793)
Treasury shares acquired, shares	2,977				2,977
Stock-based compensation activity, including tax benefit	$ 90,046		(20,628)		$ 110,674
Stock-based compensation activity, including tax benefit, shares					(1,424)
Other comprehensive loss	(29,110)					(29,110)
Net income for the year	254,690			254,690
Acquisition-related activity	(578)		(578)
Ending balance at Dec. 31, 2014	2,217,501	$ 932	904,825	1,539,508	$ (196,010)	(31,754)
Ending balance, shares at Dec. 31, 2014		93,236			2,471
Treasury shares acquired	$ (337,910)				$ (337,910)
Treasury shares acquired, shares	3,833				3,833
Stock-based compensation activity, including tax benefit	$ 79,197		(8,434)		$ 87,631
Stock-based compensation activity, including tax benefit, shares					(1,139)
Other comprehensive loss	(20,410)					(20,410)
Net income for the year	252,521			252,521
Acquisition-related activity	3,528		(1,922)		$ 5,450
Acquisition-related activity, shares					(68)
Ending balance at Dec. 31, 2015	2,194,427	$ 932	894,469	1,792,029	$ (440,839)	(52,164)
Ending balance, shares at Dec. 31, 2015		93,236			5,097
Treasury shares acquired	$ (336,335)				$ (336,335)
Treasury shares acquired, shares	3,700				3,700
Stock-based compensation activity, including tax benefit	$ 90,165		(11,459)		$ 101,624
Stock-based compensation activity, including tax benefit, shares					(1,249)
Other comprehensive loss	(5,488)					(5,488)
Net income for the year	265,636			265,636
Ending balance at Dec. 31, 2016	$ 2,208,405	$ 932	$ 883,010	$ 2,057,665	$ (675,550)	$ (57,652)
Ending balance, shares at Dec. 31, 2016		93,236			7,548