CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Rental income	$ 409,071	$ 570,382	$ 691,699
Tenant reimbursements and other income	91,609	144,509	170,158
Total revenues	500,680	714,891	861,857
Expenses:
Operating expenses	200,706	324,948	387,982
Depreciation and amortization	131,806	194,001	227,532
General and administrative	50,256	57,457	113,155
Loss on asset impairment	58,476	17,162	185,067
Acquisition related costs	0	0	5
Total expenses	441,244	593,568	913,741
Operating income (loss)	59,436	121,323	(51,884)
Interest and other income	10,331	5,989	1,561
Interest expense (including net amortization of debt discounts, premiums and deferred financing fees of $3,725, $1,028, and $(549), respectively)	(84,329)	(107,316)	(143,230)
(Loss) gain on early extinguishment of debt	(2,680)	6,661	4,909
Gain on sale of equity investment	0	0	171,561
Gain on issuance of shares by an equity investee	0	0	17,020
Foreign currency exchange loss	(5)	(8,857)	0
Gain on sale of properties, net	250,886	84,421	0
Income (loss) from continuing operations before income taxes and equity in earnings of investees	233,639	102,221	(63)
Income tax expense	(745)	(2,364)	(3,191)
Equity in earnings of investees	0	0	24,460
Income from continuing operations	232,894	99,857	21,206
Discontinued operations:
Income from discontinued operations	0	0	8,389
Loss on asset impairment from discontinued operations	0	0	(2,238)
Loss on early extinguishment of debt from discontinued operations	0	0	(3,345)
Net income	232,894	99,857	24,012
Preferred distributions	(17,956)	(27,924)	(32,095)
Excess fair value of consideration paid over carrying value of preferred shares	(9,609)	0	0
Excess fair value of consideration over carrying value of preferred shares	0	0	(16,205)
Net income (loss) attributable to Equity Commonwealth common shareholders	205,329	71,933	(24,288)
Amounts attributable to Equity Commonwealth common shareholders:
Income (loss) from continuing operations	205,329	71,933	(27,094)
Income from discontinued operations	0	0	8,389
Loss on asset impairment from discontinued operations	0	0	(2,238)
Loss on early extinguishment of debt from discontinued operations	0	0	(3,345)
Net income (loss)	$ 205,329	$ 71,933	$ (24,288)
Weighted average common shares outstanding — basic (in shares)	125,474	128,621	125,163
Weighted average common shares outstanding — diluted (in shares)	126,768	129,437	125,163
Basic earnings per common share attributable to Equity Commonwealth common shareholders:
Income (loss) from continuing operations (in dollars per share)	$ 1.64	$ 0.56	$ (0.21)
Income from discontinued operations (in dollars per share)	0.00	0.00	0.02
Net income (loss) (in dollars per share)	1.64	0.56	(0.19)
Diluted earnings per common share attributable to Equity Commonwealth common shareholders:
Income (loss) from continuing operations (in dollars per share)	1.62	0.56	(0.21)
Income from discontinued operations (in dollars per share)	0.00	0.00	0.02
Net income (loss) (in dollars per share)	$ 1.62	$ 0.56	$ (0.19)