Stock-Based Compensation - Restricted Stock Award and RSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Restricted stock awards
Restricted stock, Shares Subject to Restriction
Outstanding at the beginning of the period (in shares)	172,506
Vested (in shares)	(11,584)
Forfeited (in shares)	(4,053)
Outstanding at the end of the period (in shares)	156,869
Restricted stock, Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 19.37
Vested (in dollars per share)	19.87
Forfeited (in dollars per share)	22.46
Outstanding at the end of the period (in dollars per share)	$ 19.25
Total fair value of shares vested	$ 0.2	$ 0.2
Restricted stock units
Restricted stock, Shares Subject to Restriction
Outstanding at the beginning of the period (in shares)	262,317
Granted (in shares)	59,679
Vested (in shares)	(8,526)
Forfeited (in shares)	(17,293)
Outstanding at the end of the period (in shares)	296,177
Restricted stock, Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 22.32
Granted (in dollars per share)	22.34
Vested (in dollars per share)	22.71
Forfeited (in dollars per share)	22.47
Outstanding at the end of the period (in dollars per share)	$ 22.31
Total fair value of shares vested	$ 0.2	$ 0.0