Debt - Activity Related to Repurchase of Debt and Net Loss on Early Extinguishment of Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Original principal amount	$ 1,881,200	$ 1,818,400	$ 3,712,900
Cash purchase/repayment price	1,984,500	1,991,500	3,982,800
Losses on early extinguishment of debt, net	86,303	165,300	277,014
Senior Notes [Member]
Debt Instrument [Line Items]
Original principal amount	709,700	1,290,400	2,142,000
Cash purchase/repayment price	789,000	1,460,300	2,411,900
Term Loan [Member]
Debt Instrument [Line Items]
Original principal amount	600,000
Cash purchase/repayment price	600,000
Secured Mortagage Debt [Member]
Debt Instrument [Line Items]
Original principal amount	571,500	528,000	1,570,900
Cash purchase/repayment price	$ 595,500	$ 531,200	$ 1,570,900