Income Taxes Amounts and Expiration Dates of Net Operating Loss and Tax Credit Carryforwards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015
Deferred Tax Assets, Tax Credit Carryforwards [Abstract]
State net operating loss and tax credit carryforwards		$ 40.5
U.S. alternative minimum tax credit		0.0
Total tax credit carryforwards		20.2
State net operating loss valuation allowance		$ (20.3)
Operating Loss Carryforwards Minimum Expiration Date	2015
Operating Loss Carryforwards Maximum Expiration Date	2033