Consolidated Statements of Stockholders' Equity - USD ($)	Series A Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In-Capital [Member]	Accumulated Deficit [Member]	Total
Balances at beginning of period at Dec. 31, 2016	$ 0	$ 3,000	$ 64,828,000	$ (4,392,000)	$ 60,439,000
Balances at beginning of period (in shares) at Dec. 31, 2016		3,416,508
Net income	0	$ 0	0	(72,000)	(72,000)
Reclassification of Class A and Class B common stock to common stock	0	0	0	0	0
Net proceeds from sale of preferred stock	14,009,000	0	0	0	14,009,000
Preferred stock dividend	0	0	0	(323,000)	(323,000)
Common stock dividend	0	0	0	(1,925,000)	(1,925,000)
Net issuance of unvested restricted stock	0	$ 0	(298,000)	0	(298,000)
Net issuance of unvested restricted stock (in shares)		84,639
Stock-based compensation	0	$ 1,000	1,718,000	0	1,719,000
Balances at end of period at Dec. 31, 2017	14,009,000	$ 4,000	66,248,000	(6,712,000)	73,549,000
Balances at end of period (in shares) at Dec. 31, 2017		3,501,147
Net income	0	$ 0	0	6,985,000	6,985,000
Net proceeds from sale of common stock	0	$ 6,000	193,217,000	0	193,223,000
Net proceeds from sale of common stock (in shares)		6,210,000
Preferred stock dividend	0	$ 0	0	(1,352,000)	(1,352,000)
Common stock dividend	0	0	0	(9,188,000)	(9,188,000)
Net issuance of unvested restricted stock	0	$ 0	(390,000)	0	(390,000)
Net issuance of unvested restricted stock (in shares)		64,653
Stock-based compensation	0	$ 0	1,465,000	0	1,465,000
Balances at end of period at Dec. 31, 2018	14,009,000	$ 10,000	260,540,000	(10,267,000)	264,292,000
Balances at end of period (in shares) at Dec. 31, 2018		9,775,800
Net income	0	$ 0	0	23,475,000	23,475,000
Equity component of exchangeable senior notes	0	0	5,569,000	0	5,569,000
Net proceeds from sale of common stock	0	$ 3,000	286,267,000	0	286,270,000
Net proceeds from sale of common stock (in shares)		2,825,500
Preferred stock dividend	0	$ 0	0	(1,352,000)	(1,352,000)
Common stock dividend	0	0	0	(31,800,000)	(31,800,000)
Net issuance of unvested restricted stock	0	$ 0	(939,000)	0	(939,000)
Net issuance of unvested restricted stock (in shares)		35,743
Stock-based compensation	0	$ 0	2,495,000	0	2,495,000
Balances at end of period at Dec. 31, 2019	$ 14,009,000	$ 13,000	$ 553,932,000	$ (19,944,000)	$ 548,010,000
Balances at end of period (in shares) at Dec. 31, 2019		12,637,043