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, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic earnings per share:
Net income	$ 586,970	$ 665,244	$ 270,650	$ 344,052	$ 133,934	$ 402,835	$ 384,349	$ 290,124	$ 1,866,916	$ 1,211,242	$ 558,929
Weighted-average common shares outstanding (in shares)									437,799	435,374	431,885
Basic earnings per share (in USD per share)	$ 1.34	$ 1.52	$ 0.62	$ 0.79	$ 0.31	$ 0.92	$ 0.88	$ 0.67	$ 4.26	$ 2.78	$ 1.29
Diluted earnings per share:
Net income	$ 586,970	$ 665,244	$ 270,650	$ 344,052	$ 133,934	$ 402,835	$ 384,349	$ 290,124	$ 1,866,916	$ 1,211,242	$ 558,929
Shares used in computation:
Weighted-average common shares outstanding (in shares)									437,799	435,374	431,885
Employee stock options (in shares)									13,966	15,870	14,929
Weighted-average number of shares (in shares)									451,765	451,244	446,814
Diluted earnings per share (in USD per share)	$ 1.30	$ 1.47	$ 0.60	$ 0.76	$ 0.30	$ 0.89	$ 0.85	$ 0.64	$ 4.13	$ 2.68	$ 1.25