CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Rental income	$ 70,179	$ 64,478	$ 209,362	$ 192,150
Expenses:
Real estate taxes	8,862	7,591	24,980	22,810
Utility expenses	5,408	5,483	14,186	13,330
Other operating expenses	14,867	13,854	44,046	40,031
Depreciation and amortization	20,781	18,404	61,949	54,713
Loss on impairment of real estate	230	0	230	0
Acquisition related costs	0	147	0	363
General and administrative	3,266	3,816	12,314	11,350
Total expenses	53,414	49,295	157,705	142,597
Operating income	16,765	15,183	51,657	49,553
Dividend income	304	304	911	667
Interest income	1,715	47	1,843	63
Interest expense (including net amortization of debt premiums and discounts and debt issuance costs of $990, $805, $2,605 and $2,024, respectively)	(16,055)	(12,608)	(43,599)	(32,286)
(Loss) gain on early extinguishment of debt	(1,715)	0	(1,715)	104
Gain on issuance of shares by Select Income REIT	51	72	72	88
Income (loss) from continuing operations before income taxes and equity in earnings of investees	1,065	2,998	9,169	18,189
Income tax expense	(22)	(13)	(65)	(63)
Equity in earnings of investees	9,484	8,668	20,804	28,002
Income from continuing operations	10,527	11,653	29,908	46,128
Income (loss) from discontinued operations	462	(154)	173	(429)
Income before gain on sale of property	10,989	11,499	30,081	45,699
Gain on sale of property	0	79	0	79
Net income	10,989	11,578	30,081	45,778
Other comprehensive income:
Unrealized gain on investment in available for sale securities	3,279	8,463	14,389	28,571
Equity in unrealized gain of investees	1,351	3,273	5,634	10,423
Other comprehensive income	4,630	11,736	20,023	38,994
Comprehensive income	$ 15,619	$ 23,314	$ 50,104	$ 84,772
Weighted average common shares outstanding (basic) (in shares)	96,883	71,054	79,778	71,041
Weighted average common shares outstanding (diluted) (in shares)	96,958	71,084	79,852	71,064
Per common share amounts (basic and diluted):
Income from continuing operations (in dollars per share)	$ 0.11	$ 0.16	$ 0.37	$ 0.65
Income (loss) from discontinued operations (in dollars per share)	0.00	0.00	0.00	(0.01)
Net income (in dollars per share)	$ 0.11	$ 0.16	$ 0.38	$ 0.64