Debt - Activity Related to Repurchase of Debt and Net Loss on Early Extinguishment of Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Original principal amount		$ 1,881,200	$ 1,818,400
Cash purchase/repayment price		1,984,500	1,991,500
Losses (gains) on early extinguishment of debt, net	$ (2,484)	86,303	165,300
Senior Notes [Member]
Debt Instrument [Line Items]
Original principal amount		709,700	1,290,400
Cash purchase/repayment price		789,000	1,460,300
Term Loan [Member]
Debt Instrument [Line Items]
Original principal amount		600,000	0
Cash purchase/repayment price		600,000	0
Secured Mortgage Debt [Member]
Debt Instrument [Line Items]
Original principal amount		571,500	528,000
Cash purchase/repayment price		$ 595,500	$ 531,200