Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Supplemental disclosures:
Cash paid for interest	$ 165,441	$ 176,694
Cash paid for income taxes	4,017	5,601
Non-cash investing and financing activities:
Accrued capital expenditures, tenant improvements and real estate developments	10,499	8,831
Real estate contributions to office partnership	0	17,240
Distributions declared and unpaid	105,958	85,421
Real estate investments received from lease related transactions	3,982	259
Note receivable for disposal of real estate investments	$ 4,500	$ 0