Changes in Carrying Amount of Deferred Debt Issuance Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Balance at beginning of period	$ 16,073	$ 4,635
Deferred debt issuance costs and performance guarantees	4,944	17,881
Reductions and other transfers		(181)
Interest expense-debt issuance costs	(3,892)	(6,262)
Balance at end of period	$ 17,125	$ 16,073