Noncash Investing and Financing Activities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Other Significant Noncash Transactions [Line Items]
Accrued dividends and distributions payable	$ 54,565	$ 54,490
Additions to real estate assets accrued but not yet paid	12,571	10,301
Eastgate Crossing
Other Significant Noncash Transactions [Line Items]
Assumption of mortgage loan from sale of EastGate Crossing	$ 0	$ 14,570