CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Real estate properties:
Land	$ 699,135	$ 1,531,416
Buildings and improvements	4,838,030	6,297,993
Total real estate properties, at cost, gross	5,537,165	7,829,409
Accumulated depreciation	(895,059)	(1,007,606)
Total real estate properties, at cost, net	4,642,106	6,821,803
Properties held for sale	573,531	171,832
Acquired real estate leases, net	255,812	427,756
Equity investments	517,991	184,711
Cash and cash equivalents	222,449	102,219
Restricted cash	22,101	16,626
Rents receivable, net of allowance for doubtful accounts of $7,885 and $9,962, respectively	223,769	253,394
Other assets, net	188,675	211,293
Total assets	6,646,434	8,189,634
LIABILITIES AND SHAREHOLDERS' EQUITY
Revolving credit facility	235,000	297,000
SIR revolving credit facility		95,000
Senior unsecured debt, net	1,855,900	2,972,994
Mortgage notes payable, net	914,510	984,827
Liabilities related to properties held for sale	28,734	2,339
Accounts payable and accrued expenses	165,855	194,184
Assumed real estate lease obligations, net	33,935	69,304
Rent collected in advance	27,553	35,700
Security deposits	11,976	23,860
Due to related persons	9,385	12,958
Total liabilities	3,282,848	4,688,166
Commitments and contingencies
Common shares of beneficial interest, $0.01 par value:
Common shares of beneficial interest, $0.01 par value: 350,000,000 shares authorized; 118,386,918 and 83,804,068 shares issued and outstanding, respectively	1,184	838
Additional paid in capital	4,213,474	3,585,400
Cumulative net income	2,209,840	2,386,900
Cumulative other comprehensive (loss) income	(38,331)	565
Cumulative common distributions	(3,082,271)	(2,972,569)
Cumulative preferred distributions	(573,971)	(529,367)
Total shareholder's equity attributable to CommonWealth REIT	3,363,586	3,105,428
Noncontrolling interest in consolidated subsidiary		396,040
Total shareholders' equity	3,363,586	3,501,468
Total liabilities and shareholders' equity	6,646,434	8,189,634
Series D
50,000,000 shares authorized;
Preferred shares of beneficial interest, $0.01 par value	368,270	368,270
Series E
50,000,000 shares authorized;
Preferred shares of beneficial interest, $0.01 par value	$ 265,391	$ 265,391