Stock-Based Compensation - Stock Option Summary (Details) - Employee Stock Option [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares)	956	959	1,180
Converted upon acquisition (in shares)	42
Granted (in shares)	122	135	191
Exercised (in shares)	(152)	(41)	(58)
Forfeited (in shares)	(7)	(35)	(36)
Expired (in shares)	(66)	(62)	(318)
Outstanding, ending balance (in shares)	895	956	959
Exercisable, ending balance (in shares)	629
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Converted upon acquisition (in dollars per share)	$ 51.86
Outstanding, beginning balance (in dollars per share)	47.10	$ 45.64	$ 48.31
Granted (in dollars per share)	68.21	65.94	40.40
Exercised (in dollars per share)	38.99	39.92	37.00
Forfeited (in dollars per share)	60.03	47.38	35.29
Expired (in dollars per share)	95.31	70.12	55.13
Outstanding, ending balance (in dollars per share)	47.93	$ 47.10	$ 45.64
Exercisable, ending balance (in dollars per share)	$ 42.30
Outstanding, Weighted Average Remaining Contractual Term	6 years 2 months 12 days	6 years 3 months 18 days	6 years 7 months 6 days	5 years 8 months 12 days
Exercisable, Weighted Average Remaining Contractual Term	5 years 3 months 18 days
Outstanding, Aggregate Intrinsic Value	$ 4,806	$ 21,965	$ 19,125		$ 405
Exercised, Aggregate Intrinsic Value	4,520	$ 1,071	$ 742
Exercisable, Aggregate Intrinsic Value	$ 4,417
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	$ 24.29	$ 21.99	$ 13.27
Converted upon acquisition, Weighted Average Grant Date Fair Value (in dollars per share)	$ 14.86
Expected to Vest [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, ending balance (in shares)	266
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, ending balance (in dollars per share)	$ 61.23
Outstanding, Weighted Average Remaining Contractual Term	8 years 4 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 389