Real Estate Investments Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 22, 2015
Earnings per common share from continuing operations:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)	$ 0.10	$ 0.04	$ 0.15	$ 0.01
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)	0.10	0.04	0.15	0.01
Earnings per common share:
Basic -- as reported (USD per share)	0.10	0.04	0.15	0.02
Diluted -- as reported (USD per share)	$ 0.10	$ 0.04	$ 0.15	$ 0.02
Pro Forma Properties [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Pro forma revenue	$ 152,585	$ 149,951	$ 455,141	$ 459,722
Pro forma income from continuing operations	20,308	11,525	35,954	15,914
Pro forma net income available to common shareholders	$ 18,346	$ 9,607	$ 30,305	$ 11,332
Earnings per common share from continuing operations:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)	$ 0.11	$ 0.05	$ 0.18	$ 0.05
Basic -- as pro forma (USD per share)	0.11	0.07	0.20	0.10
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)	0.11	0.05	0.18	0.05
Diluted -- as pro forma (USD per share)	0.11	0.07	0.20	0.10
Earnings per common share:
Basic -- as reported (USD per share)	0.10	0.04	0.15	0.02
Basic -- as pro forma (USD per share)	0.10	0.06	0.17	0.07
Diluted -- as reported (USD per share)	0.10	0.04	0.15	0.02
Diluted -- as pro forma (USD per share)	$ 0.10	$ 0.06	$ 0.17	$ 0.07
Broadmoor Austin Associates [Member] | General and Administrative Expense [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Acquisition Costs					$ 200