CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Shares, outstanding, beginning balance at Dec. 31, 2013	43,999,420
Common stock, value, outstanding, beginning balance at Dec. 31, 2013	$ 185
Balance at Dec. 31, 2013	666,811		$ 550,795	$ 1,390	$ 114,441
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(24,009)		0		(24,009)
Unrealized gains on available-for-sale securities, net of taxes	(368)			(368)
Unrealized gains (losses) on derivative contracts, net of taxes	(5,042)			(5,042)
Share-based compensation	47,235		47,235
Issuance of awards through employee equity incentive plans	$ 4,847	$ 5	4,842
Issuance of shares through employee equity incentive plans (in shares)	1,093,429
Issuance of shares through employee share purchase plans	$ 11,936	2	11,934
Issuance of shares through employee share purchase plan (in shares)	394,915
Income tax benefit from share options exercised	$ 342		342
Balance at Dec. 31, 2014	701,752		615,148	(4,020)	90,432
Common stock, value, outstanding, ending balance at Dec. 31, 2014	$ 192
Shares, outstanding, ending balance at Dec. 31, 2014	45,487,764
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ 92,894		0		92,894
Unrealized gains on available-for-sale securities, net of taxes	(204)			(204)
Unrealized gains (losses) on derivative contracts, net of taxes	2,555			2,555
Share-based compensation	50,764		50,764
Issuance of awards through employee equity incentive plans	$ 6,049	6	6,043
Issuance of shares through employee equity incentive plans (in shares)	1,267,244
Issuance of shares through employee share purchase plans	$ 12,818	2	12,816
Issuance of shares through employee share purchase plan (in shares)	364,746
Income tax benefit from share options exercised	$ 53		53
Balance at Dec. 31, 2015	866,681		684,824	(1,669)	183,326
Common stock, value, outstanding, ending balance at Dec. 31, 2015	$ 200
Shares, outstanding, ending balance at Dec. 31, 2015	47,119,754
Increase (Decrease) in Stockholders' Equity
Net income (loss)	$ 18,518		0		18,518
Unrealized gains on available-for-sale securities, net of taxes	342			342
Unrealized gains (losses) on derivative contracts, net of taxes	399			399
Share-based compensation	66,309		66,309
Issuance of awards through employee equity incentive plans	$ 5,090	7	5,083
Issuance of shares through employee equity incentive plans (in shares)	1,463,884
Issuance of shares through employee share purchase plans	$ 17,465	$ 2	17,463
Issuance of shares through employee share purchase plan (in shares)	491,968
Income tax benefit from share options exercised	$ (46)		(46)
Fair value of awards attributable to pre-acquisition services	972		972
Balance at Dec. 31, 2016	975,730		$ 774,605	$ (928)	$ 201,844
Common stock, value, outstanding, ending balance at Dec. 31, 2016	$ 209
Shares, outstanding, ending balance at Dec. 31, 2016	49,075,606.000