Net Income per Share (Net Income Per Basic and Diluted Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator
Net income	$ (10,336)	$ 13,907	$ 4,148	$ 55,887	$ 100,574	$ 69,459	$ 78,264	$ 84,498	$ 63,606	$ 332,795	$ 322,244
Income used to compute net income per diluted share									$ 63,606	$ 332,795	$ 322,244
Denominator
Total weighted-average shares used to compute net income per basic share (in Shares)									163,805	163,386	158,224
Diluted (in Shares)									164,192	163,554	173,110
Net income per basic share (in Dollars per Share)	$ (0.06)	$ 0.08	$ 0.03	$ 0.34	$ 0.61	$ 0.42	$ 0.48	$ 0.52	$ 0.39	$ 2.04	$ 2.04
Net income per diluted share (in Dollars per Share)	$ (0.06)	$ 0.08	$ 0.03	$ 0.34	$ 0.61	$ 0.42	$ 0.47	$ 0.50	$ 0.39	$ 2.03	$ 1.86
Debt Instrument [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants									0	0	5,510
Series 2012 Notes [Member]
Debt Instrument [Line Items]
Assumed conversion of debt notes (in Shares)									0	0	3,532
May 2015 Notes [Member]
Debt Instrument [Line Items]
Assumed conversion of debt notes (in Shares)									0	0	5,697
Stock Options [Member]
Debt Instrument [Line Items]
Additional shares included in the calculation of diluted EPS (in Shares)									0	16	21
Restricted Stock [Member]
Debt Instrument [Line Items]
Additional shares included in the calculation of diluted EPS (in Shares)									387	152	126