Income Per Share - (Narrative) (Details) - $ / shares	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Mar. 31, 2016
Shares outstanding	28,810,883	26,788,833	28,810,883
Outstanding stock options to purchase common stock	2,703,752	1,683,867	2,703,752	2,185,922
Outstanding stock options to purchase common stock, per share	$ 19.82	$ 20.61	$ 19.82	$ 19.81
Warrants granted, exercise price per share	$ 20.00	$ 20.00	$ 20.00	$ 20.00	$ 20.00
Restricted shares outstanding		256,064	918,890
Warrant [Member]
Dilutive Convertible Securities	13,476	16,627	3,166