Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Supplemental disclosures:
Cash paid for interest	$ 50,638	$ 67,588
Cash paid for income taxes	1,404	384
Non-cash investing and financing activities:
Unsettled share issuances	0	6,650
Accrued capital expenditures, tenant improvements and real estate developments	14,856	10,903
Accrued deferred financing costs	345	0
Real estate contributions to Office Partnership	7,494	0
Distributions declared and unpaid	150,493	139,764
Real estate investments received from lease related transactions	$ 259	$ 0