Basis of Presentation and Significant Accounting Policies - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands		9 Months Ended
	Jul. 01, 2015	Sep. 30, 2015	Sep. 30, 2014
Schedule Of Supplemental Cash Flow [Line Items]
Net cash paid for income taxes		$ 5,860	$ 5,427
Cash paid for interest expense		2,806	91
Acquisition-related activities:
Cash paid for acquisitions, excluding contingent consideration		71,869	22,653
Cash acquired in acquisitions		(6,389)	(1,908)
Net cash paid for acquisitions		65,480	20,745
Non-cash investing and financing activities:
Non-cash settlement of vacation liabilities by issuing restricted stock units ("RSUs")		1,353
Property and equipment received, but not paid		1,497	561
Total Non-cash investing and financing activities		2,850	$ 561
Reggiani Macchine [Member]
Acquisition-related activities:
Net cash paid for acquisitions	$ 26,600
Common stock issued in connection with the Reggiani acquisition		$ 26,858