Deferred Revenue And Customer Advances (Schedule Of Deferred Revenue And Customer Advances) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 01, 2012	Dec. 31, 2011
Deferred Revenue And Customer Advances [Abstract]
Customer advances	$ 65,789	$ 70,001
Maintenance, training and extended warranty	37,408	33,953
Undelivered elements	7,211	7,939
Acceptance	99	318
Total deferred revenue and customer advances	$ 110,507	$ 112,211

Refundable consideration, usually cash, held by the entity pending satisfactory completion of the entity's obligations or pending the closing of a contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.15a)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Name:	us-gaap_CustomerAdvancesAndDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant