Financial Instruments and Fair Value Measurements - Debt Instruments with Carrying Values Different than Estimated Fair Values (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	$ 2,913,217	$ 3,149,188
Revolving Credit Facilities and term loans	598,242	807,185
Mortgage indebtedness	982,509	1,183,164
Total indebtedness	4,493,968	5,139,537
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	3,056,896	3,292,723
Revolving Credit Facilities and term loans	601,131	811,666
Mortgage indebtedness	1,012,869	1,235,139
Total indebtedness	$ 4,670,896	$ 5,339,528