Share-Based Compensation - Summary of Stock Options Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of shares vested and exercisable	515,977	557,311	410,236
Options vested and exercisable weighted average remaining contractual life	5 years 11 months 12 days	5 years 4 months 6 days	5 years 5 months 1 day
Options vested and exercisable weighted average exercise price	$ 21.88	$ 16.82	$ 10.57
Options vested and exercisable intrinsic value	$ 6,811	$ 11,080	$ 9,224
$5.67 - 32.80
Range of exercise prices, lower range	$ 5.67
Range of exercise prices, upper range	$ 32.80
Number of shares vested and exercisable	456,223
Options vested and exercisable weighted average remaining contractual life	5 years 8 months 19 days
Options vested and exercisable weighted average exercise price	$ 20.25
Options vested and exercisable intrinsic value	$ 6,757
$32.85 - 34.10
Range of exercise prices, lower range	$ 32.85
Range of exercise prices, upper range	$ 34.10
Number of shares vested and exercisable	42,552
Options vested and exercisable weighted average remaining contractual life	7 years 5 months 19 days
Options vested and exercisable weighted average exercise price	$ 33.95
Options vested and exercisable intrinsic value	$ 47
$34.15 - 42.94
Range of exercise prices, lower range	$ 34.15
Range of exercise prices, upper range	$ 42.94
Number of shares vested and exercisable	17,202
Options vested and exercisable weighted average remaining contractual life	8 years 3 months 18 days
Options vested and exercisable weighted average exercise price	$ 35.19
Options vested and exercisable intrinsic value	$ 7
$4.54 - 22.76
Range of exercise prices, lower range		$ 4.54
Range of exercise prices, upper range		$ 22.76
Number of shares vested and exercisable		424,130
Options vested and exercisable weighted average remaining contractual life		4 years 4 months 10 days
Options vested and exercisable weighted average exercise price		$ 12.41
Options vested and exercisable intrinsic value		$ 10,303
$23.57 - 32.85
Range of exercise prices, lower range		$ 23.57
Range of exercise prices, upper range		$ 32.85
Number of shares vested and exercisable		107,456
Options vested and exercisable weighted average remaining contractual life		8 years 3 months 22 days
Options vested and exercisable weighted average exercise price		$ 30.10
Options vested and exercisable intrinsic value		$ 709
$32.90 - 37.30
Range of exercise prices, lower range		$ 32.90
Range of exercise prices, upper range		$ 37.30
Number of shares vested and exercisable		25,725
Options vested and exercisable weighted average remaining contractual life		9 years 2 months 9 days
Options vested and exercisable weighted average exercise price		$ 34.07
Options vested and exercisable intrinsic value		$ 68
$4.54 - 20.92
Range of exercise prices, lower range			$ 4.54
Range of exercise prices, upper range			$ 20.92
Number of shares vested and exercisable			338,308
Options vested and exercisable weighted average remaining contractual life			4 years 9 months
Options vested and exercisable weighted average exercise price			$ 8.03
Options vested and exercisable intrinsic value			$ 8,465
$20.96 - 26.50
Range of exercise prices, lower range			$ 20.96
Range of exercise prices, upper range			$ 26.50
Number of shares vested and exercisable			71,928
Options vested and exercisable weighted average remaining contractual life			8 years 6 months 22 days
Options vested and exercisable weighted average exercise price			$ 22.50
Options vested and exercisable intrinsic value			$ 759