Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 145		$ 139
Mortgage loan premium	3,196	[1]	4,026	[1]
Preferred shares of beneficial interest, liquidation preference value	$ 350,000		$ 350,000
Preferred shares of beneficial interest, par value (usd per share)	$ 0.01		$ 0.01
Preferred shares of beneficial interest, shares authorized	100,000,000		100,000,000
Preferred shares of beneficial interest, shares issued	14,000,000		14,000,000
Preferred shares of beneficial interest, shares outstanding	14,000,000		14,000,000
Common shares of beneficial interest, par value (usd per share)	$ 0.01		$ 0.01
Common shares of beneficial interest, shares authorized	500,000,000		500,000,000
Common shares of beneficial interest, shares issued	71,735,129		71,553,481
Common shares of beneficial interest, shares outstanding	71,735,129		71,553,481

[1] Loan premiums on assumed mortgages recorded in purchase accounting for the Hotel Palomar San Francisco, Embassy Suites San Diego Bay - Downtown, Hotel Modera, and The Nines, a Luxury Collection Hotel, Portland.