Noncontrolling Interest (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Abstract]
Common stock, conversion term	6 months
Common stock, conversion basis (in shares)	1
EQC Operating Trust
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by parent	99.96%	99.96%	99.97%