Fair Value Measurements - Debt Instruments with Carrying Values Different than Estimated Fair Values (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	$ 2,911,277	$ 3,149,188
Revolving Credit Facilities and term loans	862,711	807,185
Mortgage indebtedness	1,164,819	1,183,164
Total indebtedness	4,938,807	5,139,537
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	3,147,137	3,292,723
Revolving Credit Facilities and term loans	866,867	811,666
Mortgage indebtedness	1,222,427	1,235,139
Total indebtedness	$ 5,236,431	$ 5,339,528