Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 26, 2019
Document Information [Line Items]
Entity Registrant Name	GORMAN RUPP CO
Entity Central Index Key	0000042682
Trading Symbol	grc
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding (in shares)		26,124,393
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false