CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Consolidated net income		$ 51,095	$ 62,307	$ 22,003
Other comprehensive income (loss):
Foreign currency translation adjustments, net of tax	[1]	(4,172)	8,909	(7,524)
Pension liability adjustments, net of tax	[2]	(475)	926	(1,361)
Total other comprehensive income (loss)		(4,647)	9,835	(8,885)
Total consolidated comprehensive income		46,448	72,142	13,118
Less: Comprehensive income attributable to noncontrolling interest		(1,986)	(2,256)
Comprehensive income attributable to Novanta Inc.		$ 44,462	$ 69,886	$ 13,118

[1] The tax effect on this component of comprehensive income was ($93), ($94) and $36 in 2018, 2017 and 2016, respectively.

[2] The tax effect on this component of comprehensive income was ($153), $277 and ($462) in 2018, 2017 and 2016, respectively.