Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Earnings Per Share [Abstract]
Net income	$ 80,245	$ 57,804	[1]	$ 63,103	[2]
Average common shares:
Basic (weighted-average outstanding shares) (in shares)	11,837,000	11,782,000	[1]	11,729,000	[1]
Dilutive potential common shares from stock options (in shares)	59,000	63,000		71,000
Diluted (weighted-average outstanding shares) (in shares)	11,896,000	11,845,000	[1]	11,800,000	[1]
Basic earnings per share (in dollars per share)	$ 6.78	$ 4.91	[1]	$ 5.38	[1]
Diluted earnings per share (in dollars per share)	$ 6.75	$ 4.88	[1]	$ 5.35	[1]
Stock options excluded from diluted earnings per share calculation (in shares)	15,586	9,864		4,244

[1] Years ended December 31, 2020 and 2019 amounts have been adjusted to reflect the change in inventory accounting method, as described in Note 1 to the Consolidated Financial Statements. 

[2] Years ended December 31, 2020 and 2019 amounts have been adjusted to reflect the change in inventory accounting method, as described in Note 1 to the Consolidated Financial Statements.