Fair Value Measurements (Additional Fair Value Information Relating To Company's Financial Instruments Outstanding) (Detail) (USD $) In Millions, unless otherwise specified	Apr. 03, 2015		Jan. 02, 2015		Apr. 04, 2014	Jan. 03, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	$ 2.3	[1]	$ 3.7	[1]
Cash and Cash Equivalents, at Carrying Value	145.7		148.0		165.2	147.2
Long-term Debt	663.4		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	422.6		396.9
Revolving Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	133.0		277.0
Line of Credit Facility, Fair Value of Amount Outstanding	133.0		277.0
Uncommitted Facilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	133.0		57.0
Short-term Debt	133.0		57.0
Short-term Debt, Fair Value	133.0		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	0.4		7.6
Long-term Debt	0.4		7.6
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability			0
Cash and cash equivalents	145.7		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	4.2
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	$ 10.5

[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 $10.5 million at the end of the first quarter of fiscal 2015, based on estimated future revenues or other milestones based on quantities sold. Contingent consideration liabilities are included in Other current liabilities and Other non-current liabilities on the Company's Condensed Consolidated Balance Sheets.