Value of input used to measure securitized mortgage collateral.

No definition available.

Name:	imh_SecuritizedMortgageCollateralMeasurementInput
Namespace Prefix:	imh_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Value of input used to measure debt instrument, including, but not limited to, convertible and non-convertible debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Value of input used to measure derivative asset.

+ References

+ Details

Name:	us-gaap_DerivativeAssetMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Value of input used to measure long-term debt.

+ References

+ Details

Name:	us-gaap_LongTermDebtMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Value of input used to measure servicing asset.

+ References

+ Details

Name:	us-gaap_ServicingAssetMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=imh_SecuritizedMortgageBorrowingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
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:

- Details

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

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputLossSeverityMember
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:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_LongTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

Fair Value of Financial Instruments - Valuation Techniques And Unobservable Inputs Applied (Details) - Level 3	Jun. 30, 2022	Dec. 31, 2021 USD ($)
Securitized mortgage borrowings \| Measurement Input, Default Rate \| Minimum
Unobservable input
Measurement input, securitized mortgage borrowings		0.0006
Securitized mortgage borrowings \| Measurement Input, Default Rate \| Maximum
Unobservable input
Measurement input, securitized mortgage borrowings		0.043
Securitized mortgage borrowings \| Measurement Input, Default Rate \| Weighted Average
Unobservable input
Measurement input, securitized mortgage borrowings		0.017
Securitized mortgage borrowings \| Measurement Input, Loss Severity \| Minimum
Unobservable input
Measurement input, securitized mortgage borrowings		0.0001
Securitized mortgage borrowings \| Measurement Input, Loss Severity \| Maximum
Unobservable input
Measurement input, securitized mortgage borrowings		0.976
Securitized mortgage borrowings \| Measurement Input, Loss Severity \| Weighted Average
Unobservable input
Measurement input, securitized mortgage borrowings		0.701
Securitized mortgage borrowings \| Measurement Input, Discount Rate \| Minimum
Unobservable input
Measurement input, securitized mortgage borrowings		0.021
Securitized mortgage borrowings \| Measurement Input, Discount Rate \| Maximum
Unobservable input
Measurement input, securitized mortgage borrowings		0.130
Securitized mortgage borrowings \| Measurement Input, Discount Rate \| Weighted Average
Unobservable input
Measurement input, securitized mortgage borrowings		0.036
Long-term debt \| Measurement Input, Discount Rate
Unobservable input
Measurement input, long-term debt	0.142	0.086
Long-term debt \| Measurement Input, Discount Rate \| Weighted Average
Unobservable input
Measurement input, long-term debt	0.142	0.086
Securitized mortgage collateral \| Measurement Input, Prepayment Rate \| Minimum
Unobservable input
Measurement input, securitized mortgage collateral		0.029
Securitized mortgage collateral \| Measurement Input, Prepayment Rate \| Maximum
Unobservable input
Measurement input, securitized mortgage collateral		0.463
Securitized mortgage collateral \| Measurement Input, Prepayment Rate \| Weighted Average
Unobservable input
Measurement input, securitized mortgage collateral		0.107
Mortgage servicing rights \| Measurement Input, Prepayment Rate \| Minimum
Unobservable input
Measurement input, mortgage servicing rights	0.075	0.0801
Mortgage servicing rights \| Measurement Input, Prepayment Rate \| Maximum
Unobservable input
Measurement input, mortgage servicing rights	0.125	0.291
Mortgage servicing rights \| Measurement Input, Prepayment Rate \| Weighted Average
Unobservable input
Measurement input, mortgage servicing rights	0.085	0.103
Mortgage servicing rights \| Measurement Input, Discount Rate \| Minimum
Unobservable input
Measurement input, mortgage servicing rights	0.125	0.125
Mortgage servicing rights \| Measurement Input, Discount Rate \| Maximum
Unobservable input
Measurement input, mortgage servicing rights	0.150	0.150
Mortgage servicing rights \| Measurement Input, Discount Rate \| Weighted Average
Unobservable input
Measurement input, mortgage servicing rights	0.128	0.128
Interest rate lock commitments (IRLCs) \| Measurement Input, Pull-through Rate \| Minimum
Unobservable input
Measurement input, derivative assets - IRLCs, net	0.400	0.500
Interest rate lock commitments (IRLCs) \| Measurement Input, Pull-through Rate \| Maximum
Unobservable input
Measurement input, derivative assets - IRLCs, net	0.990	0.980
Interest rate lock commitments (IRLCs) \| Measurement Input, Pull-through Rate \| Weighted Average
Unobservable input
Measurement input, derivative assets - IRLCs, net	0.695	0.790