Unaudited Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2017	7,287,500
Balance at Dec. 31, 2017	$ 73	$ 6,987	$ 62,115
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			12,728	$ 12,728
Stock-based compensation expense		0
Cash distributions declared ($0.60 per share)			(4,350)
Balance (in shares) at Jun. 30, 2018	7,287,500
Balance at Jun. 30, 2018	$ 73	6,987	70,493	77,553
Balance (in shares) at Mar. 31, 2018	7,287,500
Balance at Mar. 31, 2018	$ 73	6,987	68,464
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			6,379	6,379
Stock-based compensation expense		0
Cash distributions declared ($0.60 per share)			(4,350)
Balance (in shares) at Jun. 30, 2018	7,287,500
Balance at Jun. 30, 2018	$ 73	6,987	70,493	77,553
Balance (in shares) at Dec. 31, 2018	10,187,500
Balance at Dec. 31, 2018	$ 102	80,275	8,089	88,466
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			10,242	10,242
Stock-based compensation expense		329
Cash distributions declared ($0.60 per share)			0
Balance (in shares) at Jun. 30, 2019	10,187,500
Balance at Jun. 30, 2019	$ 102	80,604	18,331	99,037
Balance (in shares) at Mar. 31, 2019	10,187,500
Balance at Mar. 31, 2019	$ 102	80,446	13,205
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			5,126	5,126
Stock-based compensation expense		158
Cash distributions declared ($0.60 per share)			0
Balance (in shares) at Jun. 30, 2019	10,187,500
Balance at Jun. 30, 2019	$ 102	$ 80,604	$ 18,331	$ 99,037