Reconciliation of Statutory Canadian Tax rate to Effective Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Effective Tax Rate Reconciliation [Line Items]
Statutory Canadian tax rate	35.00%
Income Tax Provision (benefit)	$ 13,827	$ 10,519	$ 10,394
Canada Revenue Agency
Schedule Of Effective Tax Rate Reconciliation [Line Items]
Statutory Canadian tax rate	29.00%	28.50%	27.00%
Expected income tax provision at Canadian statutory tax rate	$ 22,079	$ 9,269	$ 12,426
International tax rate differences	(2,038)	891	304
State income taxes, net	674	503	453
Withholding and other taxes	484	441	731
Permanent differences	274	179	1,000
Section 199 deduction	(1,148)	(1,063)	(1,188)
Tax credits	(984)	(1,095)	(990)
Statutory tax rate changes	2,823	(856)	95
Uncertain tax positions	(1,607)	(103)	121
Change in valuation allowance	(354)	1,202	(612)
Acquisition contingent consideration adjustments	149	762
Transaction costs	1,011	649	270
Provision to return differences	225	(93)	(617)
IRS audit			(748)
Gain on Laser Quantum acquisition	(6,586)
UK patent box	(1,646)
JK Lasers divestiture			(1,432)
Other	471	(167)	581
Income Tax Provision (benefit)	$ 13,827	$ 10,519	$ 10,394
Effective tax rate	18.20%	32.30%	22.60%