Long-term Equity-based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended
	May 02, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized		10,000,000
Shares available for grant		8,243,636
Share-based compensation expense		$ 6.4	$ 5.5	$ 5.8
Total compensation cost not yet recognized		$ 4.4
Total compensation cost not yet recognized, period for recognition		1 year 9 months 18 days
Initial grant for non-employee director, shares		4,000
Automatic annual grant, non-employee directors, options		4,000
Annual awards of deferred stock units to be issued to each non-employee director	500
Performance Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reduction in share authorization if maximum performance level is met or exceeded (shares)		517,500
Options Granted Prior to May 1, 2013 [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Automatic annual grant, non-employee directors, options, vesting period		1 year
Automatic annual grant, non-employee directors, options, expiration date		10 years