Fair Value Measurements (Additional Fair Value Information Relating To Company's Financial Instruments Outstanding) (Detail) - USD ($) $ in Millions		Oct. 02, 2015	Jan. 02, 2015	Oct. 03, 2014	Jan. 03, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[1]	$ 1.7	$ 3.7
Cash and Cash Equivalents, at Carrying Value		123.6	148.0	$ 139.5	$ 147.2
Long-term Debt		759.4	738.4
Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Noncurrent		400.0	400.0
Note Payable Fair Value		405.0	396.9
Revolving Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		211.0	277.0
Line of Credit Facility, Fair Value of Amount Outstanding		211.0	277.0
Uncommitted Facilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		150.0	57.0
Long-term Debt, Fair Value		150.0	57.0
Promissory Notes And Other Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note Payable Fair Value		1.3	7.6
Long-term Debt		1.3	7.6
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		123.6	$ 148.0
Other Noncurrent Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Asset, Noncurrent		3.5
Other Current and Non Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		$ 14.6

[1] Contingent consideration liabilities represent arrangements to pay the former owners of certain companies that Trimble acquired. The undiscounted maximum payment under the arrangements is $14.6 million at the end of the third quarter of fiscal 2015, based on estimated future revenues or other milestones. Contingent consideration liabilities are included in Other current liabilities and Other non-current liabilities on the Company's Condensed Consolidated Balance Sheets.