Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Entity-Wide Revenue from External Customers [Line Items]
Product sales	$ 313,855	$ 316,150	$ 600,362	$ 619,486
Service sales	137,610	131,477	271,561	255,744
Total net sales	451,465	447,627	871,923	875,230
Waters instrument systems [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	203,901	206,421	380,568	403,932
Chemistry [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	71,960	74,299	146,900	148,021
TA instrument systems [Member]
Entity-Wide Revenue from External Customers [Line Items]
Product sales	37,994	35,430	72,894	67,533
Waters service [Member]
Entity-Wide Revenue from External Customers [Line Items]
Service sales	124,630	119,871	246,274	233,278
TA service [Member]
Entity-Wide Revenue from External Customers [Line Items]
Service sales	$ 12,980	$ 11,606	$ 25,287	$ 22,466