XML 32 R52.htm IDEA: XBRL DOCUMENT v2.4.0.6
Reconciliation of Effective Tax Rate to Federal Statutory Tax Rate (Detail)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Schedule Of Effective Tax Rates Line Items      
U.S. federal statutory rate 35.00% 35.00% 35.00%
State taxes, net of federal benefit 2.90% 3.00% 2.50%
Nondeductible expenses 0.50% 0.60% 1.10%
Provision for valuation allowance   (0.30%)  
State law change 0.30% (0.20%) (0.30%)
Other 0.20% 0.20% (0.30%)
Net effective rate 38.90% 38.30% 38.00%