Represents the weighted average ancillary income per year, used as an input to measure fair value.

No definition available.

Name:	chfc_FairValueInputsWeightedAverageAncillaryIncomePerYear
Namespace Prefix:	chfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the weighted average cost to service per year, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	chfc_FairValueInputsWeightedAverageCostToServicePerYear
Namespace Prefix:	chfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the weighted average float rate, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	chfc_FairValueInputsWeightedAverageFloatRate
Namespace Prefix:	chfc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Loan Servicing Rights, Measurement Input

+ References

No definition available.

+ Details

Name:	chfc_LoanServicingRightsMeasurementInput
Namespace Prefix:	chfc_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of revenue from servicing real estate mortgages, credit cards, and other financial assets held by others.

+ References

No definition available.

+ Details

Name:	chfc_ServicingFeesNetExcludingPremiums
Namespace Prefix:	chfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_TransfersAndServicingAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueByAssetClassAxis=chfc_MortgageLoanServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPrepaymentRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loan Servicing Rights (Assumptions Used in Determining Fair Value) (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2018
Transfers and Servicing [Abstract]
Loan servicing fee income	$ 17,600,000	$ 18,200,000	$ 8,700,000
Mortgage
Loan servicing rights
WA Cost to service/per year	66	66
WA Ancillary income/per year	$ 31	$ 31
WA float range (as a percent)	2.50%	1.60%
Discount rate \| Mortgage \| Weighted Average
Loan servicing rights
Loan servicing rights, measurement input		0.101		0.101
Prepayment rate \| Mortgage \| Minimum
Loan servicing rights
Loan servicing rights, measurement input		0.000	0.000
Prepayment rate \| Mortgage \| Maximum
Loan servicing rights
Loan servicing rights, measurement input		0.264	0.388