Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Cover page.
Document Transition Report	false
Document Quarterly Report	true
Entity Incorporation, State or Country Code	MI
Title of 12(b) Security	Common Stock
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Registrant Name	CHEMICAL FINANCIAL CORPORATION
Entity Central Index Key	0000019612
Document Type	10-Q
Entity File Number	000-08185
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		71,558,755
City Area Code	800
Local Phone Number	867-9757
Trading Symbol	CHFC
Security Exchange Name	NASDAQ
Entity Tax Identification Number	38-2022454
Entity Address, Postal Zip Code	48226
Entity Address, Address Line One	333 W. Fort Street,
Entity Address, Address Line Two	Suite 1800
Entity Address, City or Town	Detroit,
Entity Address, State or Province	MI