Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 28, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	0-12668
Entity Registrant Name	Hills Bancorporation
Entity Incorporation, State or Country Code	IA
Entity Tax Identification Number	42-1208067
Entity Address, Address Line One	131 E. Main Street, PO Box 160
Entity Address, City or Town	Hills
Entity Address, State or Province	IA
Entity Address, Postal Zip Code	52235
City Area Code	319
Local Phone Number	679-2291
Title of 12(g) Security	No par value common stock
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 559,533,150
Entity Common Stock, Shares Outstanding (in shares)		9,219,336
Documents Incorporated by Reference	Portions of the Proxy Statement dated March 17, 2023 for the Annual Meeting of the Shareholders of the Registrant to be held April 17, 2023 (the Proxy Statement) are incorporated by reference in Part III of this Form 10-K.
Entity Central Index Key	0000732417
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false