Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Amount of income (loss) related to the effective portion of cash flow hedges recognized in other comprehensive income		$ 3,110,000	$ (2,774,000)	$ (8,501,000)
Amounts reclassified from accumulated other comprehensive income into interest and debt expense		6,449,000	10,977,000	1,070,000
Unconsolidated Joint Ventures [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Amounts reclassified from accumulated other comprehensive income into interest and debt expense		0	0	0
Amount of income (loss) related to unconsolidated joint ventures recognized in other comprehensive income	[1]	$ 152,000	$ 12,000	$ (412,000)

[1] Represents foreign currency translation adjustments. No amounts were reclassified from accumulated other comprehensive income (loss) during any of the periods set forth above.