Financial Instruments - Debt Instruments with Carrying Values Different than Estimated Fair Values (Detail) - USD ($) $ in Thousands |
Sep. 30, 2015 |
Dec. 31, 2014 |
---|---|---|
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Senior notes | $ 3,118,656 | $ 2,765,893 |
Revolving Credit Facilities and Term Loans | 895,000 | 779,009 |
Mortgage indebtedness | 1,209,921 | 1,689,805 |
Total indebtedness | 5,223,577 | 5,234,707 |
Fair Value [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Senior notes | 3,276,118 | 3,011,374 |
Revolving Credit Facilities and Term Loans | 896,899 | 786,922 |
Mortgage indebtedness | 1,239,663 | 1,741,855 |
Total indebtedness | $ 5,412,680 | $ 5,540,151 |