CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income		$ 14,989	$ 8,366	$ 39,451	$ 52,630
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	[1]	(490)	3,311	(2,482)	8,340
Pension liability adjustments, net of tax	[2]	223	(45)	978	43
Total other comprehensive income		(267)	3,266	(1,504)	8,383
Total consolidated comprehensive income		14,722	11,632	37,947	61,013
Less: Comprehensive income attributable to noncontrolling interest		(435)	(834)	(1,986)	(1,444)
Comprehensive income attributable to Novanta Inc.		$ 14,287	$ 10,798	$ 35,961	$ 59,569

[1] The tax effect on this component of comprehensive income was nominal for all periods presented.

[2] The tax effect on this component of comprehensive income was nominal for all periods presented. See Note 4 for the total amount of pension liability adjustments reclassified out of accumulated other comprehensive income (loss).