Share-Based Compensation and Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-Based Compensation and Stock Repurchases
Stock based compensation expense	$ 1.3	$ 1.1	$ 2.8	$ 2.8
Common stock repurchased (in shares)			1,250,000	670,000
Common stock repurchased, value			$ 18.7	$ 8.4
Employee Stock Option
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Expected annual dividend rate (as a percent)			1.18%
Risk-free interest rate (as a percent)			1.62%
Average expected life			5 years 8 months 12 days
Expected volatility of common stock (as a percent)			0.401%
Forfeiture rate (as a percent)			0.00%
Weighted average fair value of option grants			$ 4.75
Restricted Stock Units (RSUs) | Director
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)			36,950
Granted (in dollars per share)			$ 13.51
Long Term Incentive Plan 2010 | Employee Stock Option
Stock Compensation
Options granted (in shares)			261,473
Long Term Incentive Plan 2010 | Restricted Stock Units (RSUs)
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)			403,917
Vesting period			3 years
Long Term Incentive Plan 2010 | Performance Restricted Stock Units
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)			218,493
Vesting period			3 years