Cash Dividends Cash Dividends (Details) (USD $)	9 Months Ended
Jan. 31, 2013
Cash Dividends [Abstract]
Special Cash Dividend Per Share	$ 4.00

Common Stock, Special Dividends, Per Share, Declared

No definition available.

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Namespace Prefix:	bfb_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration