Earnings Per Share - Diluted Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Diluted earnings (loss) per share
Net income (loss)	$ 1,751	$ 764	$ 3,150	$ 2,060
Weighted average shares outstanding	9,985	9,974	9,985	9,402
Basic earnings per share	$ 0.175	$ 0.077	$ 0.315	$ 0.219
Effect of dilutive securities:
Cash received for the exercise of stock options				$ 8
Less: Treasury stock purchased with assumed proceeds from exercise	6	8	6	6
Diluted weighted average shares and common stock equivalents	10,000	9,994	10,000	9,416
Diluted earnings per share	$ 0.175	$ 0.076	$ 0.315	$ 0.219
Restricted stock plan
Effect of dilutive securities:
Weighted average shares outstanding under options/ restricted stock plans	9	12	9	9
Delmar 2004 Stock Option Plan | Stock options
Effect of dilutive securities:
Weighted average shares outstanding under options/ restricted stock plans	12	23	15	31
Weighted average exercise price	$ 9.05	$ 7.54	$ 9.05	$ 10.32
Cash received for the exercise of stock options	$ 109	$ 173	$ 136	$ 320
Average market value per share	$ 7.45	$ 7.37	$ 7.30	$ 7.32
Liberty 2004 Stock Option Plan | Stock options
Effect of dilutive securities:
Weighted average shares outstanding under options/ restricted stock plans	12	16	12	11
Weighted average exercise price	$ 3.98	$ 4.02	$ 3.98	$ 4.03
Cash received for the exercise of stock options	$ 48	$ 64	$ 48	$ 44
Average market value per share	$ 7.45	$ 7.37	$ 7.30	$ 7.32