Quarterly Results (Details) - USD ($) $ / shares in Units, $ 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
Quarterly Results [Abstract]
Revenue	$ 572,200	$ 571,300	$ 560,200	$ 543,300	$ 609,600	$ 638,800	$ 650,000	$ 671,100	$ 2,247,047	$ 2,569,495	$ 3,176,718
Gross profit	450,800	418,600	449,900	438,300	503,100	529,500	494,000	564,400	1,757,537	2,091,061	2,670,912
Operating income	61,700	42,500	71,800	68,600	91,300	105,000	54,700	101,200	244,702	352,188	554,112
Net income	$ 35,800	$ 16,300	$ 44,700	$ 36,300	$ 46,500	$ 68,300	$ 19,500	$ 54,900	$ 133,046	$ 189,176	$ 364,888
Net income per share [Abstract]
Basic (in dollars per share)	$ 0.63	$ 0.28	$ 0.76	$ 0.62	$ 0.79	$ 1.15	$ 0.33	$ 0.93	$ 2.29	$ 3.20	$ 6.23
Diluted (in dollars per share)	$ 0.62	$ 0.28	$ 0.75	$ 0.60	$ 0.77	$ 1.12	$ 0.32	$ 0.90	$ 2.25	$ 3.11	$ 5.94