Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 388	$ 738
Preferred shares of beneficial interest, par value (usd per share)	$ 0.01	$ 0.01
Preferred shares of beneficial interest, liquidation preference value	$ 510,000	$ 510,000
Preferred shares of beneficial interest, authorized (in shares)	100,000,000	100,000,000
Preferred shares of beneficial interest, issued (in shares)	20,400,000	20,400,000
Preferred shares of beneficial interest, outstanding (in shares)	20,400,000	20,400,000
Common shares of beneficial interest, par value (usd per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, authorized (in shares)	500,000,000	500,000,000
Common shares of beneficial interest, issued (in shares)	130,673,300	130,484,956
Common shares of beneficial interest, outstanding (in shares)	130,673,300	130,484,956