Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 30, 2017 USD ($) Customer	Dec. 31, 2016 USD ($) Customer	Dec. 26, 2015 USD ($) Customer
Organization And Summary Of Significant Accounting Policies [Line Items]
Reserve	$ 3,000,000	$ 5,200,000
Restricted cash	$ 340,000	$ 400,000
Number of individual customer accounted for more than ten percent of account receivable balance | Customer	0	0
Number of individual customers represented more than ten percent of revenues | Customer	0	0	0
Sales to foreign distributors as a percentage of total sales	4.00%	4.00%	4.00%
Inventory on hand, purchase commitment	$ 170,300,000
Provision for excess or expired inventory	5,800,000	$ 4,500,000	$ 4,000,000
Property, plant and equipment, net	384,280,000	408,411,000
Impairment of assets	2,451,000	(235,000)	258,000
Goodwill	3,683,000	3,683,000
Decrease in refundable deposits for lost kegs and pallets	(1,000,000)	(1,100,000)
Decrease in gross property, plant and equipment	(1,000,000)	(1,400,000)
Decrease in property, plant and equipment related accumulated depreciation	(1,000,000)	(1,400,000)
Refundable deposits on kegs and pallets	12,900,000	14,300,000
Income tax expense	17,093,000	49,772,000	56,596,000
Deferred Revenue, Current	5,472,000	5,381,000
Amounts paid to customers	258,649,000	244,213,000	273,629,000
Advertising and sales promotional expenditures	128,000,000	105,300,000	120,100,000
Shipping costs	45,300,000	49,200,000	62,200,000
Stock-based compensation	6,316,000	6,148,000	6,665,000
Excess tax benefit from stock-based compensation arrangements recognized within income tax provision	4,400,000	12,524,000	$ 15,350,000
Deferred income taxes	2,200,000	$ 7,400,000
Variable customer promotional discount programs expected additional liability recorded through retained earnings	1,300,000
Contractual obligations	216,438,000
A&S brands | Product Concentration Risk | Sales Revenue, Net | Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage		5.00%	7.00%
Operating Leases
Organization And Summary Of Significant Accounting Policies [Line Items]
Contractual obligations	12,764,000	$ 15,900,000
Boston Beer Company Reporting Unit
Organization And Summary Of Significant Accounting Policies [Line Items]
Goodwill	3,700,000	3,700,000
A&S Brewing Collaborative Reporting Unit
Organization And Summary Of Significant Accounting Policies [Line Items]
intangible assets	2,000,000	2,000,000
Kegs
Organization And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, net	5,900,000	12,000,000
Distributors
Organization And Summary Of Significant Accounting Policies [Line Items]
Amounts paid to distributors	30,200,000	33,200,000	$ 33,200,000
Advertising and sales promotional expenditures	21,600,000	21,200,000	22,100,000
Reduction in revenue related to advertising, promotional and selling expenses	15,300,000	16,100,000	16,600,000
Customers programs and incentives
Organization And Summary Of Significant Accounting Policies [Line Items]
Amounts paid to customers	$ 51,800,000	$ 54,400,000	$ 55,300,000