Reconciliation of Income Tax Provision Computed at Federal Statutory Rate to Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of Statutory Federal Tax Rate [Line Items]
Federal statutory income tax rate	35.00%	35.00%	35.00%
Effect of:
State and local taxes, net of federal tax effect	2.20%	2.50%	2.70%
Other	(0.90%)	(0.90%)	(1.20%)
Effective tax rate	36.30%	36.60%	36.50%