Consolidated Statements of Cash Flows - Supplemental Information - Supplemental Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 26,634	$ 27,288
Income taxes paid	155	0
Non-Cash Activity:
Common stock dividends declared and accrued	46,167	44,563
Change in accrued property, acquisition, development, and tenant expenditures	3,481	13,845
Transfers from projects under development to operating properties	0	95,185
Transfer from land held and other assets to projects under development	$ 0	$ 29,121