Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Numerators:
Income from continuing operations	$ 34,274	$ 1,906
Less: Net income attributable to noncontrolling interest	(22)
Income from continuing operations attributable to Novanta Inc.	34,252	1,906
Net income attributable to Novanta Inc.	$ 34,252	$ 1,906
Denominators:
Weighted average common shares outstanding—basic	34,765	34,657
Dilutive potential common shares	360	196
Weighted average common shares outstanding— diluted	35,125	34,853
Basic Earnings per Share:
From continuing operations	$ 0.99	$ 0.05
Basic earnings per share attributable to Novanta Inc.	0.99	0.05
Diluted Earnings per Share:
From continuing operations	0.98	0.05
Diluted earnings per share attributable to Novanta Inc.	$ 0.98	$ 0.05