Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income per Share
Net income	$ 9,956	$ 9,942	$ 9,451	$ 9,108	$ 9,746	$ 9,459	$ 8,418	$ 8,496	$ 7,345	$ 5,760	$ 5,171	$ 5,368	$ 38,457	$ 36,119	$ 23,644
Weighted average common shares outstanding - Basic													10,508	10,403	10,709
Plus: Potential dilutive common stock equivalents (in shares)													197	143	105
Weighted average common shares outstanding - Diluted (in shares)													10,705	10,546	10,814
Net income per common share - Basic	$ 0.95	$ 0.94	$ 0.90	$ 0.87	$ 0.94	$ 0.91	$ 0.81	$ 0.81	$ 0.70	$ 0.54	$ 0.48	$ 0.49	$ 3.66	$ 3.47	$ 2.21
Net income per common share - Diluted	$ 0.93	$ 0.93	$ 0.88	$ 0.85	$ 0.93	$ 0.90	$ 0.80	$ 0.80	$ 0.69	$ 0.54	$ 0.47	$ 0.49	$ 3.59	$ 3.43	$ 2.19
Stock options and common stock excluded from the income per share calculation as their effect would have been anti-dilutive (in shares)													1,364	259	414