Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income (loss)	$ 10,294	$ 3,983			$ 31,522	$ 12,741	$ (4,418)
Other comprehensive income:
Change in fair value of interest rate swap agreements					13,708	0	0
Total other comprehensive income					13,708	0	0
Comprehensive income (loss)					45,230	12,741	(4,418)
Comprehensive (income) loss attributable to noncontrolling interests - Operating Partnership					(1,162)	(576)	695
Comprehensive (income) loss attributable to noncontrolling interests - Partially owned properties					(716)	(377)	(314)
Comprehensive income (loss) attributable to common shareholders/unitholders					43,352	11,788	(4,037)
Operating Partnership
Net income (loss)	10,294	3,983	$ 22,902	$ 6,832	31,522	12,741	(4,418)
Other comprehensive income:
Change in fair value of interest rate swap agreements	652	0	652	0	13,708	0	0
Total other comprehensive income	652	0	652	0	13,708	0	0
Comprehensive income (loss)	10,946	3,983	23,554	6,832	45,230	12,741	(4,418)
Comprehensive (income) loss attributable to noncontrolling interests - Partially owned properties					(716)	(377)	(314)
Comprehensive income attributable to noncontrolling interests	(17)	0	(17)	0
Comprehensive income (loss) attributable to common shareholders/unitholders	$ 10,929	$ 3,983	$ 23,537	$ 6,832	$ 44,514	$ 12,364	$ (4,732)