Securitized Mortgage Trusts - Securitized Mortgage Trust Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Securitized Mortgage Trust Liabilities
Securitized mortgage borrowings	$ 2,238,208	$ 2,619,210

This element represents carrying value as of the balance sheet date securitized mortgage borrowings which consist of individual tranches of bonds issued by securitization trusts and are primarily backed by mortgage loans.

No definition available.

Name:	imh_SecuritizedMortgageBorrowings
Namespace Prefix:	imh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant