Shareholders' Equity - Calculation of earning per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Shareholders' Equity
Net income	$ 3,238	$ 1,186	$ 541	$ (1,782)	$ 965	$ 1,898	$ 4,965	$ 1,081
Weighted average common shares outstanding (basic) (in shares)	2,410			2,363			2,404	2,358
Unvested restricted stock (in shares)	10			34			10	34
Weighted average common shares outstanding (diluted) (in shares)	2,420			2,397			2,414	2,392
Basic
Net income (loss) per share	$ 1.34			$ (0.75)			$ 2.07	$ 0.46
Diluted
Net income (loss) per share	$ 1.34			$ (0.75)			$ 2.06	$ 0.45