Quarterly Financial Information (Unaudited) - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected Quarterly Financial Information [Line Items]
(Provision) benefit for income taxes	$ 12,136,000	$ 12,450,000	$ 1,784,000	$ 66,292,000	$ 1,236,000	$ 16,581,000	$ (11,314,000)	$ (4,469,000)	$ 92,662,000	$ 2,034,000	$ (7,420,000)
REIT conversion costs									22,190,000	101,964,000
Loss on call spread modification related to convertible notes			4,900,000						4,869,000
Loss on extinguishment on debt		(4,200,000)							(4,181,000)
Other gains and (losses)									2,447,000	22,251,000	(916,000)
Pre-tax charge recognized									110,600,000	120,700,000	116,600,000
REIT Conversion [Member]
Selected Quarterly Financial Information [Line Items]
(Provision) benefit for income taxes				61,300,000					64,800,000
REIT Conversion Costs [Member]
Selected Quarterly Financial Information [Line Items]
REIT conversion costs			5,400,000	15,000,000	44,200,000	51,400,000	3,400,000	3,100,000
Other gains and (losses)					20,000,000
Pre-tax charge recognized					$ 8,000,000