Schedule II Valuation and Qualifying Accounts and Reserves (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for doubtful accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 1,967	$ 2,010	$ 2,319
Charges to Cost and Expenses	914	746	1,061
Deductions	888	789	1,370
Balance at End of Period	1,993	1,967	2,010
Insurance reserves
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	7,215	7,406	9,154
Charges to Cost and Expenses	1,097	854	679
Deductions	1,700	1,045	2,427
Balance at End of Period	6,612	7,215	7,406
Valuation allowance deferred tax assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	23,405	21,118	13,344
Charges to Cost and Expenses	2,972	2,287	7,774
Balance at End of Period	$ 26,377	$ 23,405	$ 21,118