Earnings Per Share - Computation of Basic and Diluted Net Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator for basic and diluted EPS:
Net income	$ 72,474	$ 15,462	$ 53,394
Denominator for basic EPS:
Weighted-average shares outstanding	20,422	20,338	20,365
Effect of dilutive securities:
Diluted potential common shares (in shares)	267	265	290
Denominator for diluted EPS:
Adjusted weighted-average shares outstanding	20,689	20,603	20,655
Basic EPS (in usd per share)	$ 3.55	$ 0.76	$ 2.62
Diluted EPS (in usd per share)	$ 3.50	$ 0.75	$ 2.59
Stock Appreciation Rights (SARs)
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)	78	39	72
Restricted Stock Units (RSUs)
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)	124	102	75
Performance-Based Restricted Stock Units
Effect of dilutive securities:
Dilutive effect of share-based compensation (in shares)	65	124	143