Reconciliation Of The Statutory Federal Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Statutory federal income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal effect	2.50%	2.20%	2.70%
Other, net	(3.50%)	(2.10%)	0.30%
Effective income tax rate	34.00%	35.10%	38.00%