Redeemable Noncontrolling Interest- Schedule of Reconciliation of Changes in Redeemable Noncontrolling Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016
Noncontrolling Interest [Abstract]
Acquisition of noncontrolling interest	$ 21,582
Net income attributable to noncontrolling interest	2,256
Adjustment of redeemable noncontrolling interest to estimated redemption value	20,244	[1]	$ 0
Foreign currency translation	2,841
Balance as of December 31, 2017	$ 46,923

[1] Adjustment of the carrying value of redeemable noncontrolling interest to the estimated redemption value was recognized in retained earnings instead of the consolidated statement of operations but was included in the computation of earnings per share attributable to Novanta Inc. (see Note 9).