Shareholders' Equity - Stock Options Activity (Details) - 2012 Equity Incentive Plan - Stock options - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Stock Options
Outstanding at beginning of the period (in shares)	2,484,400	2,165,000	2,165,000
Granted (in shares)	708,000	588,500
Exercised (in shares)	(172,250)	(15,000)
Forfeited (in shares)	(153,150)	(178,500)
Outstanding at end of the period (in shares)	2,867,000	2,560,000	2,484,400	2,165,000
Exercisable at end of the period (in shares)	1,051,125	636,250
Weighted Average Exercise Price
Outstanding at beginning of the period (in USD per share)	$ 16.22	$ 16.17	$ 16.17
Granted (in USD per share)	14.15	16.49
Exercised (in USD per share)	16.12	15.00
Forfeited (in USD per share)	16.36	16.57
Outstanding at end of the period (in USD per share)	15.70	16.23	$ 16.22	$ 16.17
Exercisable at end of the period (in USD per share)	$ 16.04	$ 15.94
Aggregate intrinsic value
Weighted average remaining life (years)	7 years 10 months 2 days	8 years 3 months 18 days	8 years	8 years 9 months 18 days
Weighted average exercisable (years)	7 years 29 days	7 years 8 months 12 days
Aggregate intrinsic value	$ 17,021	$ 557	$ 1,225	$ 1,890
Aggregate intrinsic value exercised	680	19
Aggregate intrinsic value exercisable	$ 5,885	$ 273