Consolidated Statements Of Changes In Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Beginning balance, value at Dec. 31, 2013	$ 159	$ 2,873,579	$ (17,500)	$ 1,275,206	$ 4,131,444
Beginning balance, shares at Dec. 31, 2013	158,976,784
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income (loss)				257,817	257,817
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassification Adjustment of unrealized net loss on available-for-sale securities, net of tax			1,153		(1,153)
Foreign currency translation adjustment			(19,933)		(19,933)
Shares Withheld and Retired Value		(7,315)			(7,315)
Shares withheld and retired	(267,340)
Shares Repurchased and Retired, Shares	10,246,091
Shares Repurchased and Retired, Value	$ (10)	(299,734)			(299,744)
Restricted stock units vested	95,914
Vesting of restricted stock assumed with acquisition of Complete	114,839
Exercise of stock options, value	$ 1	10,560			10,561
Exercise of stock options, shares	880,687
Tax benefit (expense) from stock-based compensation		6,160			6,160
Cash dividends declared				(37,483)	(37,483)
Share-based Compensation, Shares, net of forfeitures	152,447
Stock-based compensation expense, net of forfeitures		30,982			30,982
Shares issued under Employee Stock Purchase Plan, value		6,096			$ 6,096
Shares issued under Employee Stock Purchase Plan, shares	246,480				246,480
Ending balance, value at Dec. 31, 2014	$ 150	2,620,328	(36,280)	1,495,540	$ 4,079,738
Ending balance, shares at Dec. 31, 2014	149,648,826
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income (loss)				(1,854,718)	(1,854,718)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustment			(9,414)		(9,414)
Shares Withheld and Retired Value		(5,696)			(5,696)
Shares withheld and retired	(323,537)
Restricted stock units vested	460,400
Restricted stock forfeited, shares	(48,374)
Vesting of restricted stock assumed with acquisition of Complete	61,319
Exercise of stock options, value	$ 1	8,819			8,820
Exercise of stock options, shares	506,029
Tax benefit (expense) from stock-based compensation		(2,174)			(2,174)
Cash dividends declared				(48,984)	(48,984)
Share-based Compensation, Shares, net of forfeitures	332,534
Stock-based compensation expense, net of forfeitures		32,661			(32,661)
Shares issued to pay performance share unit, value		5,011
Shares issued to pay performance share unit, shares	224,303
Shares issued under Employee Stock Purchase Plan, value		5,568			$ 5,568
Shares issued under Employee Stock Purchase Plan, shares					332,467
Ending balance, value at Dec. 31, 2015	$ 151	2,664,517	(45,694)	(408,162)	$ 2,210,812
Ending balance, shares at Dec. 31, 2015	150,861,500
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income (loss)				(886,899)	(886,899)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustment			(34,554)		(34,554)
Shares Withheld and Retired Value		(3,669)			(3,669)
Shares withheld and retired	(364,122)
Restricted stock units vested	1,034,068
Restricted stock forfeited, shares	(1,495)
Exercise of stock options, value		524			$ 524
Exercise of stock options, shares	40,723				40,723
Tax benefit (expense) from stock-based compensation		(5,112)			$ (5,112)
Cash dividends declared				(12,476)	(12,476)
Stock-based compensation expense, net of forfeitures		30,122			30,122
Shares issued to pay performance share unit, value					5,011
Shares issued under Employee Stock Purchase Plan, value		5,172			$ 5,172
Shares issued under Employee Stock Purchase Plan, shares	290,987				290,987
Ending balance, value at Dec. 31, 2016	$ 152	2,691,553	$ (80,248)	$ (1,307,537)	$ 1,303,920
Ending balance, shares at Dec. 31, 2016	151,861,661
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Restricted Stock Units Vested, Value	$ 1	$ (1)