Computation of Net Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Computation of Net Earnings per Share
Net income available to common stockholders	$ 18,906	$ 16,480	$ 13,302	$ 11,221	$ 35,386	$ 24,523
Weighted average common shares outstanding used in computing basic income per share	33,677		33,116		33,696	32,998
Incremental options and RSUs	634		842		777	1,025
Weighted average common shares used in computing diluted net income per share	34,311		33,958		34,473	34,023
Net income per share
Basic	$ 0.56		$ 0.40		$ 1.05	$ 0.74
Diluted	$ 0.55		$ 0.39		$ 1.03	$ 0.72
Anti-dilutive common equivalent shares excluded from calculation	1,800		3,138		1,352	5,006