Income Taxes Amounts and Expiration Dates of Net Operating Loss and Tax Credit Carryforwards (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Deferred Tax Assets, Tax Credit Carryforwards [Abstract]
State net operating loss and tax credit carryforwards	$ 30.1
U.S. alternative minimum tax credit	0
Total tax credit carryforwards	11.7
State net operating loss valuation allowance	$ (18.4)
Operating Loss Carryforwards Minimum Expiration Date	2015
Operating Loss Carryforwards Maximum Expiration Date	2033