Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Document Information [Line Items]
Entity Central Index Key	0001632127
Entity Registrant Name	CABLE ONE, INC.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
Entity File Number	001-36863
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3060083
Entity Address, Address Line One	210 E. Earll Drive
Entity Address, City or Town	Phoenix
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85012
City Area Code	602
Local Phone Number	364-6000
Title of 12(b) Security	Common Stock, par value $0.01
Trading Symbol	CABO
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 4,800,000,000
Entity Common Stock, Shares Outstanding		5,724,190