Computation of Earnings Per Share, Basic (Parenthetical) (Detail)	1 Months Ended
Mar. 25, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Conversion of Class B Common Stock into Class A Common Stock	100,000

Conversion of Class B common stock to Class A common stock, Shares

No definition available.

Name:	sam_ConversionOfClassBCommonStockToClassACommonStockShares
Namespace Prefix:	sam_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration