Income Taxes - Reconciliations of Statutory U.S. Federal Income Tax Rates to Our Effective Tax Rate for Continuing Operations (Detail)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	35.00%	35.00%	35.00%
State tax, net of federal benefit	2.90%	2.60%	0.00%
Effect of state rate change on net deferred tax liabilities, net of federal benefit	4.40%	0.00%	(0.10%)
State, release valuation allowance on net operating losses	(4.00%)	0.00%	0.00%
Unrecognized tax benefits, U.S. federal and state, net of federal benefit	4.80%	0.00%	0.00%
Other, net	(1.20%)	0.60%	2.00%
Effective tax rate	41.90%	38.20%	36.90%

Effective Income Tax Rate Reconciliation, Unrecognized Tax Benefits, Net of Federal Benefit

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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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