Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2019		Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net increase (decrease) in shareholders' equity resulting from operations
Net income (loss) attributable to common stockholders	$ 17,293						$ 6,661	$ 45,345	$ 48,892
Add: Net income (loss) attributable to Convertible Non-controlling Interests	387						46	1,079	335
Net income (loss) related to common stockholders and Convertible Non-controlling Interests	17,680						6,707	46,424	49,227
Dividends Paid:
Dividends	(14,494)	[1]	$ (12,801)		$ (16,764)		(12,651)	(44,059)	(38,152)
Undistributed (Distributed in excess of) earnings:
Total undistributed (distributed in excess of) earnings	$ 3,186						$ (5,944)	$ 2,365	$ 11,075
Weighted average shares outstanding (basic and diluted):
Weighted average shares outstanding (basic and diluted) (in shares)	33,571,441							31,521,820
Basic earnings per share of common stock:
Distributed (in usd per share)	$ 0.42						$ 0.41	$ 1.39	$ 1.23
Undistributed (Distributed in excess of) (in usd per share)	0.11						(0.19)	0.08	0.35
Basic earnings per common share (in usd per share)	0.53						0.22	1.47	1.58
Diluted earnings per share of common stock:
Distributed (in usd per share)	0.42						0.41	1.39	1.23
Undistributed (Distributed in excess of) (usd per share)	0.11						(0.19)	0.08	0.35
Diluted earnings per common share (in usd per share)	$ 0.53						$ 0.22	$ 1.47	$ 1.58
Net increase (decrease) in equity resulting from operations	$ 1,000						$ 800	$ 2,400	$ 1,800
Common Stock
Net increase (decrease) in shareholders' equity resulting from operations
Net income (loss) attributable to common stockholders							6,553		48,111
Dividends Paid:
Dividends	(14,185)						(12,362)	(43,038)	(37,285)
Undistributed (Distributed in excess of) earnings:
Total undistributed (distributed in excess of) earnings	$ 3,108						$ (5,809)	$ 2,307	$ 10,826
Weighted average shares outstanding (basic and diluted):
Weighted average shares outstanding (basic and diluted) (in shares)	32,835,652						30,151,753	30,787,634	30,392,390
Long-Term Incentive Plan Units [Member]
Net increase (decrease) in shareholders' equity resulting from operations
Net income (loss) attributable to common stockholders							$ 108		$ 781
Dividends Paid:
Dividends							(202)		(606)
Undistributed (Distributed in excess of) earnings:
Total undistributed (distributed in excess of) earnings							$ (94)		$ 175
Weighted average shares outstanding (basic and diluted):
Weighted average shares outstanding (basic and diluted) (in shares)							495,212		493,257
Non-controlling Interest
Dividends Paid:
Dividends	$ (309)						$ (87)	$ (1,021)	$ (261)
Undistributed (Distributed in excess of) earnings:
Total undistributed (distributed in excess of) earnings	$ 78						$ (41)	$ 58	$ 74
Weighted average shares outstanding (basic and diluted):
Weighted average shares outstanding (basic and diluted) (in shares)	735,789						212,000	734,186	212,000

[1] For the three- and nine-month periods ended September 30, 2019, dividends totaling $0.42 and $1.39 per share of common stock outstanding were declared.