CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Rental revenue		$ 184,368,000	$ 324,415,000
Rental revenue	$ 116,869,000
Other revenue	10,981,000	12,654,000	16,156,000
Revenues, Total	127,850,000	197,022,000	340,571,000
Expenses:
Operating expenses	46,418,000	79,916,000	141,425,000
Depreciation and amortization	28,122,000	49,041,000	90,708,000
General and administrative	38,442,000	44,439,000	47,760,000
Loss on asset impairment	0	12,087,000	19,714,000
Total expenses	112,982,000	185,483,000	299,607,000
Interest and other income, net	72,392,000	46,815,000	26,380,000
Interest expense (including net amortization of debt discounts, premiums and deferred financing fees of $204, $2,553 and $3,135, respectively)	(8,908,000)	(26,585,000)	(52,183,000)
Loss on early extinguishment of debt	(6,374,000)	(7,122,000)	(493,000)
Gain on sale of properties, net	422,172,000	251,417,000	15,498,000
Income before income taxes	494,150,000	276,064,000	30,166,000
Income tax expense	(1,284,000)	(3,156,000)	(500,000)
Net income	492,866,000	272,908,000	29,666,000
Net income attributable to noncontrolling interest	(186,000)	(95,000)	(10,000)
Net income attributable to Equity Commonwealth	492,680,000	272,813,000	29,656,000
Preferred distributions	(7,988,000)	(7,988,000)	(7,988,000)
Net income attributable to Equity Commonwealth common shareholders	$ 484,692,000	$ 264,825,000	$ 21,668,000
Weighted average common shares outstanding — basic (in shares)	122,091	122,314	124,125
Weighted average common shares outstanding — diluted (in shares)	126,260	123,385	125,129
Earnings per common share attributable to Equity Commonwealth common shareholders:
Basic (in dollars per share)	$ 3.97	$ 2.17	$ 0.17
Diluted (in dollars per share)	$ 3.90	$ 2.15	$ 0.17