Stock Options, Employee Stock Purchase Plan and Restricted Stock (Details) - Stock Option Activity - Stock Option Plan 2014 And 2003 [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Beginning balance, outstanding (in shares)	4,762	6,386	9,228
Granted (in shares)	2,089	1,016	1,475
Exercised (in shares)	(1,794)	(2,519)	(4,226)
Forfeited or expired (in shares)	(292)	(121)	(91)
Ending balance, outstanding (in shares)	4,766	4,762	6,386
Number of Shares, Exercisable (in shares)	1,495
Weighted Average Exercise Price
Beginning balance, outstanding (in dollars per share)	$ 20.33	$ 11.44	$ 4.45
Granted (in dollars per share)	26.61	37.60	28.59
Exercised (in dollars per share)	7.78	4.09	1.91
Forfeited or expired (in dollars per share)	28.96	34.78	22.56
Ending balance, outstanding (in dollars per share)	27.27	$ 20.33	$ 11.44
Weighted Average Exercise Price, Exercisable (in dollars per share)	$ 23.51
Weighted Average Remaining Contractual Term (Years)	5 years 11 days
Weighted Average Remaining Contractual Term, Exercisable (Years)	3 years 1 month 6 days
Aggregate Intrinsic Value	$ 5,714
Aggregate Intrinsic Value, Exercisable	$ 5,272