Share-Based Compensation - Summary of Options Outstanding (Details) (USD $)	6 Months Ended
	Jun. 30, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Number (in shares)	337,696
Weighted Average Remaining Contractual Life	5 years 5 months 27 days
Exercisable, Number (in shares)	230,732
Weighted Average Exercise Price (in usd per share)	$ 14.12
$5.34-$5.39 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in usd per share)	$ 5.34
Range of exercise prices, maximum (in usd per share)	$ 5.39
Outstanding, Number (in shares)	37,500
Weighted Average Remaining Contractual Life	7 years 4 months 28 days
Exercisable, Number (in shares)	25,833
Weighted Average Exercise Price (in usd per share)	$ 5.39
$9.07-$9.56 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in usd per share)	$ 9.07
Range of exercise prices, maximum (in usd per share)	$ 9.56
Outstanding, Number (in shares)	128,196
Weighted Average Remaining Contractual Life	8 years 10 months 28 days
Exercisable, Number (in shares)	32,899
Weighted Average Exercise Price (in usd per share)	$ 9.07
$14.47 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (in usd per share)	$ 14.47
Outstanding, Number (in shares)	79,500
Weighted Average Remaining Contractual Life	3 years 7 months 6 days
Exercisable, Number (in shares)	79,500
Weighted Average Exercise Price (in usd per share)	$ 14.47
$15.35-$16.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in usd per share)	$ 16.00
Range of exercise prices, maximum (in usd per share)	$ 16.50
Outstanding, Number (in shares)	32,500
Weighted Average Remaining Contractual Life	2 years 5 months 19 days
Exercisable, Number (in shares)	32,500
Weighted Average Exercise Price (in usd per share)	$ 16.04
$19.10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (in usd per share)	$ 19.10
Outstanding, Number (in shares)	30,000
Weighted Average Remaining Contractual Life	1 year 7 months 2 days
Exercisable, Number (in shares)	30,000
Weighted Average Exercise Price (in usd per share)	$ 19.10
$19.17 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (in usd per share)	$ 19.17
Outstanding, Number (in shares)	30,000
Weighted Average Remaining Contractual Life	7 months 2 days
Exercisable, Number (in shares)	30,000
Weighted Average Exercise Price (in usd per share)	$ 19.17