CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Dividends in excess of net income [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-Controlling Interest [Member]
Balance at Dec. 31, 2014	$ 356,035	$ 1	$ 388,263	$ (32,584)	$ (2,060)	$ 2,415
Balance (in shares) at Dec. 31, 2014		17,539,946
Issuance of common stock, net of issuance costs	92,260	$ 1	92,259	0	0	0
Issuance of common stock, net of issuance costs (in shares)		3,043,812
Issuance of restricted stock under the Omnibus Incentive Plan	0	$ 0	0	0	0	0
Issuance of restricted stock under the Omnibus Incentive Plan (in shares)		85,597
Forfeiture of restricted stock	0	$ 0	0	0	0	0
Forfeiture of restricted stock (in shares)		(32,054)
Vesting of restricted stock	1,992	$ 0	1,992	0	0	0
Dividends and distributions declared for the period	(35,336)	0	0	(34,696)	0	(640)
Other comprehensive income (loss) - change in fair value of interest rate swaps	(1,093)	0	0	0	(1,070)	(23)
Net income	39,762	0	0	39,018	0	744
Balance at Dec. 31, 2015	453,620	$ 2	482,514	(28,262)	(3,130)	2,496
Balance (in shares) at Dec. 31, 2015		20,637,301
Issuance of common stock, net of issuance costs	228,011	$ 1	228,010	0	0	0
Issuance of common stock, net of issuance costs (in shares)		5,461,459
Repurchase of common shares	(712)	$ 0	(712)	0	0	0
Repurchase of common shares (in shares)		(20,569)
Issuance of restricted stock under the Omnibus Incentive Plan	0	$ 0	0	0	0	0
Issuance of restricted stock under the Omnibus Incentive Plan (in shares)		93,363
Forfeiture of restricted stock	0	$ 0	0	0	0	0
Forfeiture of restricted stock (in shares)		(6,577)
Vesting of restricted stock	2,257	$ 0	2,257	0	0	0
Dividends and distributions declared for the period	(46,081)	0	0	(45,414)	0	(667)
Other comprehensive income (loss) - change in fair value of interest rate swaps	2,618	0	0	0	2,594	24
Net income	45,797	0	0	45,118	0	679
Balance at Dec. 31, 2016	685,510	$ 3	712,069	(28,558)	(536)	2,532
Balance (in shares) at Dec. 31, 2016		26,164,977
Issuance of common stock, net of issuance costs	222,695	$ 0	222,695	0	0	0
Issuance of common stock, net of issuance costs (in shares)		4,786,604
Repurchase of common shares	(1,111)	$ 0	(1,111)	0	0	0
Repurchase of common shares (in shares)		(23,925)
Issuance of restricted stock under the Omnibus Incentive Plan	0	$ 0	0	0	0	0
Issuance of restricted stock under the Omnibus Incentive Plan (in shares)		88,466
Forfeiture of restricted stock	0	$ 0	0	0	0	0
Forfeiture of restricted stock (in shares)		(11,222)
Vesting of restricted stock	2,393	$ 0	2,393	0	0	0
Dividends and distributions declared for the period	(59,022)	0	0	(58,317)	0	(705)
Other comprehensive income (loss) - change in fair value of interest rate swaps	1,935	0	0	0	1,911	24
Net income	58,790	0	0	58,112	0	678
Balance at Dec. 31, 2017	$ 911,190	$ 3	$ 936,046	$ (28,763)	$ 1,375	$ 2,529
Balance (in shares) at Dec. 31, 2017		31,004,900