Interest Expense and Amortization of Deferred Debt Costs (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Debt Instrument [Line Items]
Interest incurred	$ 11,429,000	$ 12,064,000	$ 22,835,000	$ 24,392,000
Amortization of deferred debt costs	314,000	494,000	625,000	899,000
Capitalized interest	(34,000)	(4,000)	(34,000)	(3,600)
Interest expense and amortization of deferred debt costs	$ 11,709,000	$ 12,554,000	$ 23,426,000	$ 25,287,000