CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income (loss)		$ 22,003	$ 35,615	$ (24,242)
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	[1]	(7,524)	(4,083)	(6,968)
Pension liability adjustments, net of tax	[2]	(1,361)	1,709	(3,146)
Total other comprehensive income (loss)		(8,885)	(2,374)	(10,114)
Total consolidated comprehensive income (loss)		13,118	33,241	(34,356)
Less: Comprehensive income attributable to noncontrolling interest				(10)
Comprehensive income (loss) attributable to Novanta Inc.		$ 13,118	$ 33,241	$ (34,366)

[1] The tax effect on this component of comprehensive income was $36, $193 and $622 in 2016, 2015 and 2014, respectively.

[2] The tax effect on this component of comprehensive income was ($462), $307 and ($906) in 2016, 2015 and 2014, respectively.