Condensed Consolidated Statements of Shareholders Equity - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2016	$ 4,301,996	$ 3,745	$ 1,375,290	$ (260)	$ 2,923,221
Balance, shares at Dec. 31, 2016	374,492,357	374,492,357
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU 2016-09 cumulative effect on retained earnings	$ 5,150				5,150
Net income (unaudited)	469				469
Other Comprehensive Income (Loss), Net of Tax (unaudited)	138			138
Stock-based compensation (unaudited)	11,428		11,428
Restricted stock:
Granted (unaudited)	$ 11	$ 11
Granted (unaudited), shares	1,151,041	1,151,041
Repurchased and canceled (unaudited)	$ (9,837)	$ (2)	(9,835)
Repurchased and canceled (unaudited), shares	(212,280)	(212,280)
Forfeited (unaudited), shares	(109,987)	(109,987)
Forfeitures (unaudited)	$ (1)	$ (1)
Balance at Mar. 31, 2017	$ 4,309,354	$ 3,753	$ 1,376,883	$ (122)	$ 2,928,840
Balance, shares at Mar. 31, 2017	375,321,131	375,321,131