Computation of Net Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Computation of Net Earnings per Share
Net income available to common stockholders	$ 10,785	$ 13,302	$ 11,221	$ 704	$ 556	$ 6,062	$ 35,308	$ 7,322
Weighted average common shares outstanding used in computing basic income per share	33,477			32,344			33,159	32,584
Incremental options and RSUs	697			979			911	1,237
Weighted average common shares used in computing diluted net income per share	34,174			33,323			34,070	33,821
Net income per share
Basic	$ 0.32			$ 0.02			$ 1.06	$ 0.22
Diluted	$ 0.32			$ 0.02			$ 1.04	$ 0.22
Anti-dilutive common equivalent shares excluded from calculation	848			847,448			8,226	236,229