Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 10, 2021
Cover [Abstract]
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	000-50368
Entity Registrant Name	Air Transport Services Group, Inc.
Entity Central Index Key	0000894081
Current Fiscal Year End Date	--03-31
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1631624
Entity Address, Address Line One	145 Hunter Drive
Entity Address, City or Town	Wilmington
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45177
City Area Code	937
Security Exchange Name	NASDAQ
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
Local Phone Number	382-5591
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	ATSG
Entity Common Stock, Shares Outstanding		74,202,989
Document Quarterly Report	true
Document Information [Line Items]
Document Period End Date	Mar. 31, 2021