Income Taxes Difference of Income Taxes from Statutory Federal Income Tax Rates (Details)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal U.S. income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit	4.20%	4.30%	4.00%
Non-deductible expenses	0.60%	0.70%	0.80%
Non-U.S. income taxed at different rates, net of foreign tax credits	(0.20%)	(1.00%)	0.70%
Federal tax credits	(0.60%)	(1.30%)	(0.30%)
Tax impact of uncertain tax positions	(0.10%)	0.10%	(1.20%)
Valuation allowance release, net	(0.30%)	(1.00%)	0.00%
Other, net	(0.10%)	(0.20%)	0.00%
Effective tax rate	38.50%	36.60%	39.00%

Effective income tax rate reconciliation tax impact of uncertain tax position

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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