Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net income	$ 47,319	$ 87,651	$ 80,459
Denominator:
Weighted average shares outstanding - basic (in shares)	18,573,000	18,374,000	18,154,000
Effect of dilutive shares (in shares)	140,000	285,000	393,000
Weighted average shares outstanding - diluted (in shares)	18,713,000	18,659,000	18,547,000
Basic earnings per share (in dollars per share)	$ 2.55	$ 4.77	$ 4.43
Diluted earnings per share (in dollars per share)	$ 2.53	$ 4.70	$ 4.34
Antidilutive securities excluded from computation of earnings per share (in shares)	20,520	36,642	0