Share-based Compensation Plans - Stock Options (Details) - Stock options - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of shares
Options outstanding, at the beginning of the period (in shares)	932,553
Granted (in shares)	36,022
Forfeited (in shares)	(56,484)
Exercised (in shares)	(115,176)
Options outstanding, at the end of the period (in shares)	796,915	932,553
Exercisable, at the end of the period (in shares)	416,829
Vested and expected to vest , at the end of the period (in shares)	774,424
Weighted Average Exercise Price
Options outstanding, at the beginning of the period (in dollars per share)	$ 7.19
Granted (in dollars per share)	7.27
Forfeited (in dollars per share)	7.36
Exercised (in dollars per share)	7.17
Options outstanding, at the end of the period (in dollars per share)	7.19	$ 7.19
Exercisable, at the end of the period (in dollars per share)	6.93
Vested and expected to vest , at the end of the period (in dollars per share)	$ 7.18
Average Remaining Life (years)
Outstanding, at end of period	6 years 8 months 23 days
Exercisable, at the end of the period	5 years 5 months 9 days
Vested and expected to vest, at the end of the period	6 years 8 months 5 days
Average Intrinsic Value
Outstanding, at the end of the period	$ 4,189,266
Exercisable, at the end of the period	2,342,931
Vested and expected to vest, at the end of the period	4,080,984
Aggregate intrinsic value of options exercised
Total intrinsic value of options exercised	500,000	$ 200,000	$ 200,000
Income tax benefit recognized related to share-based compensation	$ 100,000	$ 100,000
Minimum
Summary of the expenses the Company has recognized related to share-based compensation
Vesting period	3 years
Maximum
Summary of the expenses the Company has recognized related to share-based compensation
Vesting period	5 years