Related Person Transactions (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended		1 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Jun. 30, 2013 item	Jun. 30, 2012	Jun. 30, 2013 item	Jun. 30, 2012	Mar. 31, 2013 RMR	Jun. 30, 2013 RMR agreement	Jun. 30, 2012 RMR	Jun. 30, 2013 RMR agreement	Jun. 30, 2012 RMR	Mar. 15, 2013 CWH	Jun. 30, 2013 CWH	Jun. 30, 2013 AIC item	Jun. 30, 2012 AIC	Jun. 30, 2013 AIC item	Jun. 30, 2012 AIC	Dec. 31, 2012 AIC
Related Party Transaction
Number of employees		0		0
Number of agreements to avail management and administrative services							2		2
Percentage of interest in subsidiaries												100.00%
Expenses incurred pursuant to our business management agreement							$ 2,528	$ 2,028	$ 4,982	$ 4,258
Number of shares issued for the incentive fee for services rendered	20,230					20,230
Property management and construction supervision fees incurred							1,799	1,610	3,615	3,205
Number of other companies owning interest in equity method investment													5		5
Shares sold by former parent company											9,950,000
Common shares registration and sale expenses paid by related party											303
Amount invested in equity investee													5,194		5,194
Investment at carrying value													5,823		5,823		5,747
Recognized income (loss) related to investment in AIC		79	76	155	121								79	76	155	121
Coverage of purchased property insurance															500,000
Premium for property insurance															$ 1,161
Percentage of interest													12.50%		12.50%
Program extension term															1 year