CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 425,507	$ 210,597
Other comprehensive income, net of tax:
Unrealized gain on marketable securities	0	342
Total comprehensive income	425,507	210,939
Comprehensive income attributable to the noncontrolling interest	(748)	(79)
Total comprehensive income attributable to Equity Commonwealth	$ 424,759	$ 210,860