Organization and Summary of Significant Accounting Policies (Computation of Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Basic earnings per share:
Net income	$ 43,178	$ 29,432	$ 26,335	$ 23,696	$ 83,371	$ 59,295	$ 71,018	$ 53,115	$ 122,641	$ 266,799	$ 112,403
Weighted-average common shares outstanding									425,889	420,544	407,385
Basic earnings per share (in USD per share)	$ 0.10	$ 0.07	$ 0.06	$ 0.06	$ 0.20	$ 0.14	$ 0.17	$ 0.13	$ 0.29	$ 0.63	$ 0.28
Diluted earnings per share:
Net income	$ 43,178	$ 29,432	$ 26,335	$ 23,696	$ 83,371	$ 59,295	$ 71,018	$ 53,115	$ 122,641	$ 266,799	$ 112,403
Convertible Notes interest expense, net of tax									0	0	49
Numerator for diluted earnings per share									$ 122,641	$ 266,799	$ 112,452
Shares used in computation:
Weighted-average common shares outstanding									425,889	420,544	407,385
Convertible Notes shares									0	0	5,007
Employee stock options									10,567	11,350	12,935
Weighted-average number of shares									436,456	431,894	425,327
Diluted earnings per share (in USD per share)	$ 0.10	$ 0.07	$ 0.06	$ 0.05	$ 0.19	$ 0.14	$ 0.16	$ 0.12	$ 0.28	$ 0.62	$ 0.26