Selected Quarterly Financial Data (Schedule Of Selected Quarterly Financial Data) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 30, 2011	Sep. 30, 2011	Jul. 01, 2011	Apr. 01, 2011	Dec. 31, 2010	Oct. 01, 2010	Jul. 02, 2010	Apr. 02, 2010	Dec. 30, 2011	Dec. 31, 2010	Jan. 01, 2010
Selected Quarterly Financial Data [Abstract]
Revenue	$ 435,170	$ 417,433	$ 407,169	$ 384,293	$ 323,349	$ 318,210	$ 333,363	$ 319,015	$ 1,644,065	$ 1,293,937	$ 1,126,259
Gross margin	217,758	211,559	208,734	191,530	163,330	159,748	163,426	158,997	829,581	645,501	549,868
Net income attributable to Trimble Navigation Ltd.	$ 29,403	$ 27,971	$ 53,678	$ 39,703	$ 36,564	$ 32,845	$ 6,353	$ 27,898	$ 150,755	$ 103,660	$ 63,446
Basic net income per share	$ 0.24	$ 0.23	$ 0.44	$ 0.33	$ 0.30	$ 0.27	$ 0.05	$ 0.23	$ 1.23	$ 0.86	$ 0.53
Diluted net income per share	$ 0.23	$ 0.22	$ 0.43	$ 0.32	$ 0.29	$ 0.27	$ 0.05	$ 0.23	$ 1.20	$ 0.84	$ 0.52