CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income		$ 11,625	$ 9,990	$ 24,462	$ 44,264
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	[1]	(5,663)	3,589	(1,992)	5,029
Pension liability adjustments, net of tax	[2]	871	(117)	755	88
Total other comprehensive income		(4,792)	3,472	(1,237)	5,117
Total consolidated comprehensive income		6,833	13,462	23,225	49,381
Less: Comprehensive income attributable to noncontrolling interest		(625)	(588)	(1,551)	(610)
Comprehensive income attributable to Novanta Inc.		$ 6,208	$ 12,874	$ 21,674	$ 48,771

[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).