Earnings Per Share - Summary of weighted average number of shares outstanding (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income	$ 23,171	$ 17,292	$ 64,318	$ 40,609
Denominator:
Weighted average common shares outstanding (in shares)	16,868	16,698	16,828	16,670
Weighted average dilutive securities (in shares)	299	184	304	128
Weighted average common shares outstanding, diluted (in shares)	17,167	16,882	17,132	16,798
Income per common share:
Basic (in dollars per share)	$ 1.37	$ 1.04	$ 3.82	$ 2.44
Diluted (in dollars per share)	$ 1.35	$ 1.02	$ 3.75	$ 2.42