Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 28, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
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	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2019
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 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
Local Phone Number	382-5591
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	ATSG
Entity Public Float			$ 1,416,475,681
Entity Common Stock, Shares Outstanding		59,329,431
Documents Incorporated by Reference [Text Block]	Portions of the Proxy Statement for the Annual Meeting of Stockholders scheduled to be held May 7, 2020 are incorporated by reference into Parts II and III.