Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Total Shareholders’ Equity	Common Shares	Additional Paid - In Capital	Retained earnings (distributions in excess of retained earnings)	Noncontrolling Interest in Operating Partnership
Beginning Balance (in shares) at Dec. 31, 2016			38,367,014
Beginning Balance at Dec. 31, 2016	$ 681,590	$ 676,742	$ 380	$ 722,019	$ (45,657)	$ 4,848
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares pursuant to Equity Incentive Plan (in shares)			23,980
Issuance of shares pursuant to Equity Incentive Plan	500	500		500
Issuance of shares, net of offering costs (in shares)			829,723
Issuance of shares, net of offering costs	16,359	16,359	$ 8	16,351
Issuance of restricted time-based shares (in shares)			5,000
Issuance of restricted time-based shares	0
Amortization of share based compensation	1,536	421		421		1,115
Dividends declared on common shares	(25,464)	(25,464)			(25,464)
Distributions declared on LTIP units ($0.66 per unit)	(465)					(465)
Reallocation of noncontrolling interest	0	185		185		(185)
Net income	9,713	9,647			9,647	66
Ending Balance (in shares) at Jun. 30, 2017			39,225,717
Ending Balance at Jun. 30, 2017	683,769	678,390	$ 388	739,476	(61,474)	5,379
Beginning Balance (in shares) at Dec. 31, 2017			45,375,266
Beginning Balance at Dec. 31, 2017	809,780	803,162	$ 450	871,730	(69,018)	6,618
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares pursuant to Equity Incentive Plan (in shares)			21,670
Issuance of shares pursuant to Equity Incentive Plan	500	500		500
Issuance of shares, net of offering costs (in shares)			479,876
Issuance of shares, net of offering costs	10,425	10,425	$ 9	10,416
Amortization of share based compensation	1,863	86		86		1,777
Dividends declared on common shares	(30,294)	(30,294)			(30,294)
Distributions declared on LTIP units ($0.66 per unit)	(601)					(601)
Forfeited distributions declared on LTIP units	652					652
Reallocation of noncontrolling interest	0	20		20		(20)
Net income	16,353	16,233			16,233	120
Ending Balance (in shares) at Jun. 30, 2018			45,876,812
Ending Balance at Jun. 30, 2018	$ 808,678	$ 800,132	$ 459	$ 882,752	$ (83,079)	$ 8,546