XML 17 R37.htm IDEA: XBRL DOCUMENT v2.4.0.6
Commitments and Contingencies - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Commitments and Contingencies Disclosure [Line Items]    
Self-insurance reserves $ 5,073 $ 4,631