Fair Values of Financial Instruments - Summary of Reconciliation of Acquisition Related Contingent Consideration (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Payment of acquisition related contingent consideration		$ 16,738	$ 13,550	$ 4,039
(Favorable)/unfavorable fair value adjustment		3,226	(1,910)	3,576
Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Opening balance - Level 3 liability		253,437	136,570
Measurement period adjustment	[1]	14,826
Payment of acquisition related contingent consideration		(16,738)	(13,550)
Reclassification to current payables		(2,340)	(1,530)
(Favorable)/unfavorable fair value adjustment		3,226	(1,910)
Ending balance - Level 3 liability		381,291	253,437	$ 136,570
Level 3 [Member] | System Transformation Transactions [Member]
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Increase due to acquisitions	[2]	$ 128,880	$ 133,857

[1] Measurement period adjustments relate to post-closing adjustments made in accordance with the terms and conditions of the applicable asset purchase agreement or asset exchange agreement for each System Transformation Transaction.

[2] Increase due to System Transformation Transactions acquisitions includes an increase in the acquisition related contingent consideration of $62.5 million in 2017 from the opening balance sheets for the Expansion Territories and Expansion Facilities acquired in the System Transformation during 2017, as disclosed in the financial statements in the Company’s filed periodic reports. These adjustments are for post-closing adjustments made in accordance with the terms and conditions of the applicable asset purchase agreement or asset exchange agreement for each System Transformation Transaction.