Stock-Based Compensation - Restricted Stock Award and RSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted stock awards
Restricted stock, Shares Subject to Restriction
Outstanding at the beginning of the period (in shares)	243,150
Granted (in shares)	13,105
Vested (in shares)	(82,374)
Forfeited (in shares)	(1,375)
Outstanding at the end of the period (in shares)	172,506	243,150
Restricted stock, Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 18.58
Granted (in dollars per share)	24.80
Vested (in dollars per share)	17.95
Forfeited (in dollars per share)	16.57
Outstanding at the end of the period (in dollars per share)	$ 19.37	$ 18.58
Total fair value of shares vested	$ 1.5	$ 1.0	$ 3.0
Unrecognized pre-tax stock-based compensation expense	$ 2.5
Weighted average remaining service period	2 years 1 month 24 days
Restricted stock units
Restricted stock, Shares Subject to Restriction
Granted (in shares)	262,475
Vested (in shares)	0
Forfeited (in shares)	(158)
Outstanding at the end of the period (in shares)	262,317
Restricted stock, Weighted Average Grant Date Fair Value
Granted (in dollars per share)	$ 22.33
Forfeited (in dollars per share)	26.29
Outstanding at the end of the period (in dollars per share)	$ 22.32
Unrecognized pre-tax stock-based compensation expense	$ 5.1
Weighted average remaining service period	3 years 9 months
Minimum | Restricted stock awards
Restricted stock, Weighted Average Grant Date Fair Value
Period of service restrictions	1 year
Maximum | Restricted stock awards
Restricted stock, Weighted Average Grant Date Fair Value
Period of service restrictions	5 years