Financial Instruments and Fair Value Measurements - Debt Instruments with Carrying Values Different than Estimated Fair Values (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	$ 3,060,345	$ 2,913,217
Revolving Credit Facilities and term loans	598,266	598,242
Mortgage indebtedness	908,055	982,509
Total indebtedness	4,566,666	4,493,968
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	3,169,530	3,056,896
Revolving Credit Facilities and term loans	601,321	601,131
Mortgage indebtedness	933,534	1,012,869
Total indebtedness	$ 4,704,385	$ 4,670,896