Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Disclosures:
Cash paid for interest	$ 137,477	$ 150,107
Cash paid for income taxes	8,365	15,846
Non-cash investing and financing activities:
Accrued capital expenditures and real estate developments	2,582	4,059
Accrued deferred financing costs	0	2,696
Accrued repurchases of common stock to settle tax obligation	208	0
Distributions declared and unpaid	143,420	133,398
Mortgage note payable relieved by foreclosure	38,315	2,450
Mortgage notes payable assumed in real estate disposition	66,000	55,000
Nonmonetary Exchanges:
Intangible lease liability received	(159)	0
Real estate investments received	50,212	0
Real estate investments relinquished and gain on disposition	(47,474)	0
Rent and tenant receivables and other assets, net relinquished	(2,602)	0
Intangible lease liability relinquished	242	0
Real estate investments received from a ground lease expiration	$ 259	$ 0