Shareholders Equity - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	6 Months Ended
Dec. 09, 2011	May 15, 2008	Sep. 29, 2012
Equity Note
Share repurchase, authorized	$ 20.0	$ 20.0
Dividend paid, total amount			$ 4.7

Equity impact of common stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Name:	us-gaap_DividendsCommonStockCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration