Stock Compensation Plans - Restricted and Performance Based Stock Awards (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock Awards
Summary of non-vested stock awards
Nonvested as of beginning of year (in shares)	204,689
Granted (in shares)	159,938
Vested (in shares)	(103,152)
Forfeited (in shares)	(10,935)
Nonvested as of end of year (in shares)	250,540	204,689
Nonvested stock awards, Weighted-Average Grant Date Fair Value
Nonvested as of beginning of year (in dollars per share)	$ 20.28
Granted (in dollars per share)	14.65	$ 21.06	$ 20.83
Vested (in dollars per share)	19.56
Forfeited (in dollars per share)	19.43
Nonvested as of end of year (in dollars per share)	$ 17.02	$ 20.28
Stock Awards
Total grant date fair value amount of awards granted	$ 2.3	$ 2.4	$ 2.1
Total fair value amount of awards vested	$ 2.0	2.0	1.5
Restricted Stock Awards | Time vested
Stock Compensation Plans
Vesting period	3 years
Performance stock awards | Return on Capital
Stock Compensation Plans
Vesting period	3 years
Expense recognized	$ 0.0	$ 0.0	$ 0.0
Summary of non-vested stock awards
Vested (in shares)	0	0	0
Nonvested stock awards, Weighted-Average Grant Date Fair Value
Nonvested as of beginning of year (in dollars per share)	$ 19.33
Granted (in dollars per share)	13.76	$ 20.74	$ 20.54
Forfeited (in dollars per share)	17.56
Nonvested as of end of year (in dollars per share)	$ 17.56	$ 19.33
Stock Awards
Total grant date fair value amount of awards granted	$ 0.5	$ 0.5	$ 0.6
Performance stock awards | Return on Capital | Minimum
Stock Compensation Plans
Vesting percentage	0.00%
Performance stock awards | Return on Capital | Maximum
Stock Compensation Plans
Vesting percentage	200.00%
Performance stock awards | Return on Capital | Target
Summary of non-vested stock awards
Nonvested as of beginning of year (in shares)	76,942
Granted (in shares)	35,719
Forfeited (in shares)	(32,713)
Nonvested as of end of year (in shares)	79,948	76,942
Performance stock awards | Total Stockholder Return
Stock Compensation Plans
Vesting period	3 years	3 years	3 years
Nonvested stock awards, Weighted-Average Grant Date Fair Value
Nonvested as of beginning of year (in dollars per share)	$ 21.74
Granted (in dollars per share)	9.66	$ 21.96	$ 21.39
Vested (in dollars per share)	21.92
Forfeited (in dollars per share)	21.79
Nonvested as of end of year (in dollars per share)	$ 15.09	$ 21.74
Stock Awards
Total grant date fair value amount of awards granted	$ 0.5	$ 0.5	$ 0.6
Total fair value amount of awards vested	$ 0.5	$ 0.2	$ 0.1
Performance stock awards | Total Stockholder Return | Minimum
Stock Compensation Plans
Vesting percentage	0.00%
Performance stock awards | Total Stockholder Return | Maximum
Stock Compensation Plans
Vesting percentage	200.00%
Performance stock awards | Total Stockholder Return | Target
Summary of non-vested stock awards
Nonvested as of beginning of year (in shares)	68,505
Granted (in shares)	50,880
Vested (in shares)	(22,248)
Forfeited (in shares)	(4,093)
Nonvested as of end of year (in shares)	93,044	68,505