Related Party Transactions - Agreements with Anheuser-Busch, LLC (Details) $ / shares in Units, $ in Thousands		3 Months Ended		4 Months Ended	9 Months Ended		12 Months Ended
	Aug. 23, 2016 USD ($) barrel $ / shares $ / case $ / barrel	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Proposed sale of stock, price per share minimum on or prior to August 23, 2017 (usd per share) | $ / shares	$ 22.00
Proposed sale of stock, price per share minimum during August 23, 2017 to August 23, 2018 (usd per share) | $ / shares	23.25
Proposed sale of stock, price per share minimum on or after August 24, 2018 (usd per share) | $ / shares	$ 24.50
Anheuser-Busch Worldwide Investments, LLC (ABWI) | International Distribution Agreement | Forecast
Related Party Transaction [Line Items]
Fees to be collected from related party per agreement | $				$ 3,000			$ 6,000	$ 5,000
Anheuser-Busch Worldwide Investments, LLC (ABWI) | International Distribution Agreement | Minimum
Related Party Transaction [Line Items]
Royalty fee per barrel (usd per barrel) | $ / barrel	30
Anheuser-Busch Worldwide Investments, LLC (ABWI) | International Distribution Agreement | Maximum
Related Party Transaction [Line Items]
Royalty fee per barrel (usd per barrel) | $ / barrel	40
Affiliated entity | A - B Commercial Strategies, LLC (ABCS) | Contract Brewing Agreement
Related Party Transaction [Line Items]
Number of barrels to be brewed, bottled and packaged by affiliate (maximum) | barrel	300,000
Cost savings per barrel required to share cost savings per agreement | $ / barrel	10.00
Number of days for prior written notice to terminate agreement	90 days
Number of days following receipt of qualifying offer	120 days
Period in which affiliate can terminate agreement	3 years
Affiliated entity | Anheuser-Busch Worldwide Investments, LLC (ABWI)
Related Party Transaction [Line Items]
Fees to be collected from related party per agreement | $		$ 900	$ 0		$ 900	$ 0
Affiliated entity | Anheuser-Busch Worldwide Investments, LLC (ABWI) | International Distribution Agreement
Related Party Transaction [Line Items]
Number of days for prior written notice to terminate agreement	90 days
Number of days following receipt of qualifying offer	120 days
Period to lapse for possible one-time payment to be paid	3 years
Possible one-time payment to be paid by affiliate to the Company | $	$ 20,000
Affiliated entity | Anheuser-Busch, LLC | Master Distributor Agreement [Member]
Related Party Transaction [Line Items]
Number of days following receipt of qualifying offer	120 days
Period in which affiliate can terminate agreement	3 years
Margin fee per case (usd per case) | $ / case	0.25
Margin fee per case removed by amended agreement (usd per case) | $ / case	0.75
Amount per case to be reinvested (usd per case) | $ / case	0.25