Required and Actual Financial Ratios Under Senior Secured Credit Facility (Detail) (Senior Secured Credit Facility)	Jun. 30, 2011 Point
Required Ratio | Maximum
Debt Disclosure [Line Items]
Maximum consolidated leverage ratio	3.50
Required Ratio | Minimum
Debt Disclosure [Line Items]
Minimum consolidated interest coverage ratio	3.00
Actual Ratio | Maximum
Debt Disclosure [Line Items]
Maximum consolidated leverage ratio	1.90
Actual Ratio | Minimum
Debt Disclosure [Line Items]
Minimum consolidated interest coverage ratio	7.25