Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2015	$ 73	$ 6,987	$ 38,254	$ 45,314
Balance (in shares) at Dec. 31, 2015	7,287,500
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	16,817	16,817
Cash distributions declared	$ 0	0	(6,995)	(6,995)
Balance (in shares) at Dec. 31, 2016	7,287,500
Balance at Dec. 31, 2016	$ 73	6,987	48,076	55,136
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	23,789	23,789
Cash distributions declared	$ 0	0	(9,749)	(9,749)
Balance (in shares) at Dec. 31, 2017	7,287,500
Balance at Dec. 31, 2017	$ 73	6,987	62,116	69,176
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 0	0	25,000	25,000
Common stock issued, net of offering costs (in shares)	2,900,000
Common stock issued, net of offering costs	$ 29	50,125	0	50,154
Capital injection	0	137	0	137
Reclassification of undistributed S Corporation earnings	0	22,872	(22,872)	0
Stock-based compensation expense	0	154	0	154
Cash distributions declared	$ 0	0	(56,155)	(56,155)
Balance (in shares) at Dec. 31, 2018	10,187,500
Balance at Dec. 31, 2018	$ 102	$ 80,275	$ 8,089	$ 88,466