Stock-Based Compensation - Summary Stock Options Outstanding and Exercisable (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares) | shares	472,156
Options outstanding, Weighted Average Remaining Contractual Life	3 years 259 days
Exercise price range(in dollars per share)	$ 30.41
Options exercisable (in shares) | shares	394,363
Options exercisable, weighted average exercise price (in dollars per share)	$ 21.86
$6.22 - $6.22
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	6.22
Exercise price range, upper limit (in dollars per share)	$ 6.22
Options outstanding (in shares) | shares	157,750
Options outstanding, Weighted Average Remaining Contractual Life	1 year 47 days
Exercise price range(in dollars per share)	$ 6.22
Options exercisable (in shares) | shares	157,750
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.22
$11.59 - $12.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	11.59
Exercise price range, upper limit (in dollars per share)	$ 11.59
Options outstanding (in shares) | shares	105,480
Options outstanding, Weighted Average Remaining Contractual Life	2 years 62 days
Exercise price range(in dollars per share)	$ 12.04
Options exercisable (in shares) | shares	105,480
Options exercisable, weighted average exercise price (in dollars per share)	$ 12.04
$19.6 - $65.36
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	12.21
Exercise price range, upper limit (in dollars per share)	$ 12.21
Options outstanding (in shares) | shares	105,986
Options outstanding, Weighted Average Remaining Contractual Life	5 years 73 days
Exercise price range(in dollars per share)	$ 39.89
Options exercisable (in shares) | shares	89,629
Options exercisable, weighted average exercise price (in dollars per share)	$ 36.47
$65.45 - $73.52
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	19.60
Exercise price range, upper limit (in dollars per share)	$ 28.79
Options outstanding (in shares) | shares	67,140
Options outstanding, Weighted Average Remaining Contractual Life	7 years 172 days
Exercise price range(in dollars per share)	$ 71.46
Options exercisable (in shares) | shares	32,550
Options exercisable, weighted average exercise price (in dollars per share)	$ 71.65
$85.99 - $85.99
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	38.4
Exercise price range, upper limit (in dollars per share)	$ 38.4
Options outstanding (in shares) | shares	35,800
Options outstanding, Weighted Average Remaining Contractual Life	8 years 55 days
Exercise price range(in dollars per share)	$ 85.99
Options exercisable (in shares) | shares	8,954
Options exercisable, weighted average exercise price (in dollars per share)	$ 85.99