Computation of Net Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Computation of Net Earnings per Share
Net income available to common stockholders	$ 704	$ 556	$ 6,062	$ 8,838	$ 14,669	$ 13,915	$ 7,322	$ 37,422
Weighted average common shares outstanding used in computing basic income per share	32,344			32,365			32,584	32,225
Incremental options and RSUs	979			1,608			1,237	1,807
Weighted average common shares used in computing diluted net income per share	33,323			33,973			33,821	34,032
Net income per share
Basic	$ 0.02			$ 0.27			$ 0.22	$ 1.16
Diluted	$ 0.02			$ 0.26			$ 0.22	$ 1.10
Weighted average number diluted shares outstanding adjustment	800			300			200	11