Fair Values of Financial Instruments (Summary of unobservable inputs) (Details)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 1,643,832,000	$ 1,214,635,000
Mortgage loans on real estate, held for investment (Allowance for credit losses of $1,577 in 2023.)	421,232,000	227,047,000
Other Invested assets	126,777,000	112,431,000
Preferred stock	33,926,000	31,415,000
Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	684,597,000	558,972,000
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans on real estate, held for investment (Allowance for credit losses of $1,577 in 2023.)	421,232,000	227,047,000
Other Invested assets	114,013,000	99,997,000
Preferred stock	22,986,000	$ 21,871,000
Preferred Stock, Valuation Technique [Extensible Enumeration]		us-gaap:MarketApproachValuationTechniqueMember
Preferred Stock, Measurement Input [Extensible Enumeration]		EBITDA Multiple
Fair Value, Inputs, Level 3 | Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	684,597,000	$ 558,972,000
Fair Value, Inputs, Level 3 | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)		0.080
Fair Value, Inputs, Level 3 | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)		0.255
Fair Value, Inputs, Level 3 | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)		0.145
Fair Value, Inputs, Level 3 | Non performance risk | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 146,100,000	$ 111,600,000
Embedded Derivative Liability, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueOptionPricingModelMember	us-gaap:ValuationTechniqueOptionPricingModelMember
Fair Value, Inputs, Level 3 | Non performance risk | Minimum | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.006	0.006
Fair Value, Inputs, Level 3 | Non performance risk | Maximum | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.015	0.015
Fair Value, Inputs, Level 3 | Non performance risk | Weighted average | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.011	0.011
Fair Value, Inputs, Level 3 | Option budget | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.011	0.011
Fair Value, Inputs, Level 3 | Option budget | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.059	0.057
Fair Value, Inputs, Level 3 | Option budget | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.029	0.027
Fair Value, Inputs, Level 3 | Discount rates | Preferred equity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 9,800,000	$ 6,100,000
Embedded Derivative Liability, Valuation Technique [Extensible List]	mdwt:ValuationTechniqueYieldAnalysisMember	mdwt:ValuationTechniqueYieldAnalysisMember
Embedded Derivative Liability, Measurement Input [Extensible Enumeration]	Discount rates	Discount rates
Fair Value, Inputs, Level 3 | Discount rates | Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 684,600,000	$ 559,000,000.0
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	mdwt:ValuationTechniqueYieldAnalysisMember	mdwt:ValuationTechniqueYieldAnalysisMember
Debt Securities, Available-for-Sale, Measurement Input [Extensible Enumeration]	Discount rates	Discount rates
Fair Value, Inputs, Level 3 | Discount rates | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	0.080
Fair Value, Inputs, Level 3 | Discount rates | Minimum | Preferred equity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.240	0.240
Fair Value, Inputs, Level 3 | Discount rates | Minimum | Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, term loans (as a percent)	0.046	0.046
Fair Value, Inputs, Level 3 | Discount rates | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	0.255
Fair Value, Inputs, Level 3 | Discount rates | Maximum | Preferred equity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.280	0.280
Fair Value, Inputs, Level 3 | Discount rates | Maximum | Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, term loans (as a percent)	0.173	0.173
Fair Value, Inputs, Level 3 | Discount rates | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	0.145
Fair Value, Inputs, Level 3 | Discount rates | Weighted average | Preferred equity
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.260	0.260
Fair Value, Inputs, Level 3 | Discount rates | Weighted average | Term loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, term loans (as a percent)	0.124	0.124
Fair Value, Inputs, Level 3 | EBITDA Multiple
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Invested assets	$ 114,000,000.0	$ 100,000,000.0
Alternative Investment, Valuation Technique [Extensible Enumeration]	us-gaap:MarketApproachValuationTechniqueMember	us-gaap:MarketApproachValuationTechniqueMember
Preferred stock	$ 10,700,000	$ 31,400,000
Preferred Stock, Valuation Technique [Extensible Enumeration]	us-gaap:MarketApproachValuationTechniqueMember
Preferred Stock, Measurement Input [Extensible Enumeration]	EBITDA Multiple
Fair Value, Inputs, Level 3 | EBITDA Multiple | Detachable warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total fixed maturities	$ 2,500,000	$ 2,200,000
Embedded Derivative Liability, Valuation Technique [Extensible List]	us-gaap:MarketApproachValuationTechniqueMember	us-gaap:MarketApproachValuationTechniqueMember
Embedded Derivative Liability, Measurement Input [Extensible Enumeration]	EBITDA Multiple	EBITDA Multiple
Fair Value, Inputs, Level 3 | EBITDA Multiple | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	2.6	2.6
Fair Value, Inputs, Level 3 | EBITDA Multiple | Minimum | Detachable warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.100	10.0
Interest sensitive contract liabilities, preferred stock (as a percent)	2.55	2.55
Fair Value, Inputs, Level 3 | EBITDA Multiple | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	3.1	3.1
Fair Value, Inputs, Level 3 | EBITDA Multiple | Maximum | Detachable warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.115	11.5
Interest sensitive contract liabilities, preferred stock (as a percent)	3.05	3.05
Fair Value, Inputs, Level 3 | EBITDA Multiple | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, other invested assets (as a percent)	2.8	2.8
Fair Value, Inputs, Level 3 | EBITDA Multiple | Weighted average | Detachable warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	1.000	1.000
Interest sensitive contract liabilities, preferred stock (as a percent)	2.8	2.8
Fair Value, Inputs, Level 3 | Surrender rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.005	0.005
Fair Value, Inputs, Level 3 | Surrender rate | Maximum | Base | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.15	0.15
Fair Value, Inputs, Level 3 | Surrender rate | Maximum | Additional Shock | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.30	0.30
Fair Value, Inputs, Level 3 | Surrender rate | Weighted average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest sensitive contract liabilities, embedded derivative (as a percent)	0.125	0.105
Fair Value, Inputs, Level 3 | Principal funded
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans on real estate, held for investment (Allowance for credit losses of $1,577 in 2023.)	$ 421,200,000	$ 227,000,000.0
Mortgage Loans on Real Estate, Valuation Technique [Extensible Enumeration]	mdwt:ValuationTechniqueYieldAnalysisMember	mdwt:ValuationTechniqueYieldAnalysisMember
Mortgage Loans on Real Estate, Measurement Input [Extensible Enumeration]	Principal funded	Principal funded