Sale Leaseback Transaction (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Mar. 31, 2007	Sep. 30, 2004	Dec. 31, 2014 extension
Sale Leaseback Transaction [Abstract]
Sale leaseback transaction, net proceeds	$ 58.1	$ 9.7
Sales leaseback transaction, carrying value of property sold	20.3	8.5
Sales leaseback transaction, transaction gain recognized	1.3
Sale leaseback transaction, total transaction gain	37.4
Sale leaseback transaction, transaction gain deferred	36.1
Lease expiration date			2022
Number of option lease extensions			2
Option lease extension period (in years)			5 years
Sale leaseback transaction, annual rental payments			4.2
Sale leaseback transaction, annual rent escalation percentage (as a percent)			2.00%
Sale leaseback transaction, future annual rental payments beginning on April First Two Thousand and Seventeen			$ 4.5
Sale leaseback transaction, future annual rent increase prcentage beginning on April First Two Thousand and Seventeen (as a percent)			2.00%