v3.26.1

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 27, 2026	Dec. 26, 2025
Statement of Financial Position [Abstract]
Allowance for Credits	$ 6.5	$ 6.0

Allowance for Credits: Includes allowance for doubtful accounts and other credits against receivables.

No definition available.

Name:	ggg_AllowanceforCredits
Namespace Prefix:	ggg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	us-gaap_StatementOfFinancialPositionAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration