Stock-Based Compensation (Details) (Stock options, USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Options outstanding, Beginning of period (in shares)	162,404
Number of Shares, Granted (in shares)	0
Number of Shares, Exercised (in shares)	(67,111)
Number of Shares, Cancelled (in shares)	0
Number of Shares, Options outstanding, End of period (in shares)	95,293	162,404
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Beginning of period (in dollars per share)	$ 8.90
Weighted Average Exercise Price, Granted (in dollars per share)	$ 0.00
Weighted Average Exercise Price, Exercised (in dollars per share)	$ 8.95
Weighted Average Exercise Price, Cancelled (in dollars per share)	$ 0.00
Weighted Average Exercise Price, End of period (in dollars per share)	$ 8.86	$ 8.90
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Terms, Options outstanding (in years)	3 years 1 month 3 days	3 years 3 months 10 days
Aggregate Intrinsic Value, Options outstanding	$ 1.8	$ 3.0