Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Per Share
Net income	$ 8,605	$ 9,664	$ 17,502	$ 19,102
Weighted average basic shares outstanding	1,835	1,854	1,844	1,854
Add: Effect of dilutive securities	4,000	10,000	5,000	9,000
Weighted average diluted shares outstanding	1,839	1,864	1,849	1,863
Earnings per share:
Basic	$ 4.69	$ 5.21	$ 9.49	$ 10.30
Diluted	$ 4.68	$ 5.18	$ 9.47	$ 10.25