Computation of Net Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Computation of Net Earnings per Share
Net income available to common stockholders	$ 13,302	$ 11,221	$ 556	$ 6,062	$ 24,523	$ 6,618
Weighted average common shares outstanding used in computing basic income per share	33,116		32,729		32,998	32,706
Incremental options and RSUs	842		1,172		1,025	1,358
Weighted average common shares used in computing diluted net income per share	33,958		33,901		34,023	34,064
Net income per share
Basic	$ 0.40		$ 0.02		$ 0.74	$ 0.20
Diluted	$ 0.39		$ 0.02		$ 0.72	$ 0.19
Anti-dilutive common equivalent shares excluded from calculation	3,138		239,314		5,006	12,213