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, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory rate	35.00%	35.00%	35.00%
State tax, net of federal benefit	3.10%	3.00%	2.90%
Impact of state rate change on net deferred tax liabilities, net of federal benefit	(0.50%)	0.50%	4.40%
State, valuation allowance adjustments on net operating losses	1.00%	(0.20%)	(4.00%)
Unrecognized tax benefits, U.S. federal and state, net of federal benefit	1.60%	(0.50%)	4.80%
Other, net	(0.60%)	(0.30%)	(1.20%)
Effective tax rate	39.60%	37.50%	41.90%