CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:
Rental income	$ 707,380	$ 709,390	$ 601,632
Tenant reimbursements and other income	178,156	172,515	139,712
Total revenues	885,536	881,905	741,344
Expenses:
Operating expenses	370,869	356,604	297,408
Depreciation and amortization	218,854	209,759	171,662
General and administrative	77,209	46,057	38,221
Loss on asset impairment			3,036
Acquisition related costs	318	5,648	9,731
Total expenses	667,250	618,068	520,058
Operating income	218,286	263,837	221,286
Interest and other income	1,229	1,404	1,662
Interest expense (including net amortization of debt discounts, premiums and deferred financing fees of $9, $3,296 and $6,751, respectively)	(173,011)	(201,840)	(191,876)
Loss on early extinguishment of debt	(60,052)	(287)	(35)
Gain on sale of equity investment	66,293
Gain on issuance of shares by an equity investee		7,246	11,177
Income from continuing operations before income tax expense and equity in earnings of investees	52,745	70,360	42,214
Income tax expense	(2,634)	(3,207)	(1,347)
Equity in earnings of investees	25,754	11,420	11,377
Income from continuing operations	75,865	78,573	52,244
Discontinued operations:
Income from discontinued operations	15,867	9,783	22,307
Loss on asset impairment from discontinued operations	(227,122)	(168,632)	(7,319)
Loss on early extinguishment of debt from discontinued operations	(1,011)	(1,608)
Net (loss) gain on sale of properties from discontinued operations	(22,162)	2,039	42,752
(Loss) income before gain on sale of properties	(158,563)	(79,845)	109,984
Gain on sale of properties	1,596
Net (loss) income	(156,967)	(79,845)	109,984
Net income attributable to noncontrolling interest in consolidated subsidiary	(20,093)	(15,576)
Net (loss) income attributable to CommonWealth REIT	(177,060)	(95,421)	109,984
Preferred distributions	(44,604)	(51,552)	(46,985)
Excess redemption price paid over carrying value of preferred shares		(4,985)
Net (loss) income	(221,664)	(151,958)	62,999
Amounts attributable to CommonWealth REIT common shareholders:
Income from continuing operations	12,764	6,460	5,259
Income from discontinued operations	15,867	9,783	22,307
Loss on asset impairment from discontinued operations	(227,122)	(168,632)	(7,319)
Loss on early extinguishment of debt from discontinued operations	(1,011)	(1,608)
Net (loss) gain on sale of properties from discontinued operations	(22,162)	2,039	42,752
Net (loss) income	$ (221,664)	$ (151,958)	$ 62,999
Weighted average common shares outstanding - basic and diluted (in shares)	112,378	83,750	77,428
Basic and diluted earnings per common share attributable to CommonWealth REIT common shareholders:
Income from continuing operations (in dollars per share)	$ 0.11	$ 0.08	$ 0.07
(Loss) income from discontinued operations (in dollars per share)	$ (2.09)	$ (1.89)	$ 0.75
Net (loss) income (in dollars per share)	$ (1.97)	$ (1.81)	$ 0.81