Debt Instrument, Covenant Compliance, Adjusted Tangible Net Worth Ratio

No definition available.

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- Definition

The maximum leverage ratio required by the debt agreement, when base borrowing is required.

+ References

No definition available.

+ Details

Name:	mdc_DebtInstrumentCovenantMaximumLeverageRatioBaseBorrowingRequired
Namespace Prefix:	mdc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The minimum common stock outstanding ownership percentage required by the debt agreement.

+ References

No definition available.

+ Details

Name:	mdc_DebtInstrumentCovenantMinimumCommonStockOutstandingOwnershipPercentage
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Leverage Ratio, Base Borrowing Required

+ References

No definition available.

+ Details

Name:	mdc_LineOfCreditFacilityLeverageRatioBaseBorrowingRequired
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum amount the borrowing capacity of the facility may increase under certain conditions.

+ References

No definition available.

+ Details

Name:	mdc_LineOfCreditFacilityMaximumIncreaseToBorrowingCapacity
Namespace Prefix:	mdc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Outstanding, Extended Maturity Amount

+ References

No definition available.

+ Details

Name:	mdc_LineOfCreditFacilityOutstandingExtendedMaturityAmount
Namespace Prefix:	mdc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility subject to receipt of additional commitments from existing or additional lenders and, in the case of additional lenders, the consent of the co-administrative agents.

+ References

No definition available.

+ Details

Name:	mdc_LineOfCreditFacilityPotentialMaximumBorrowingCapacitySubjectToAdditionalCommitments
Namespace Prefix:	mdc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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_LineOfCreditFacilityLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying value as of the balance sheet date of the outstanding short-term borrowings under a revolving line of credit used by mortgage bankers to finance the origination or purchase of loans.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Balance Type:
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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=mdc_SpecifiedEurocurrencyRateMember
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Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=mdc_MortgageRepurchaseFacilityMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_WarehouseAgreementBorrowingsMember
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Data Type:	na
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- Details

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- Details

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Lines of Credit and Total Debt Obligations - Narrative (Details)	Dec. 28, 2020 USD ($)	Feb. 04, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 30, 2020	Sep. 28, 2020 USD ($)	Sep. 24, 2020 USD ($)	Sep. 23, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 24, 2019 USD ($)	Aug. 09, 2018 USD ($)	Sep. 29, 2017 USD ($)
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount			$ 127,100,000
Adjusted tangible net worth ratio						10.0	8.0
Maximum
Line of Credit Facility [Line Items]
Leverage ratio	55.00%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,200,000,000										$ 1,000,000,000.0
Potential borrowing capacity, subject to additional commitments	$ 1,700,000,000
Stated interest rate	0.00%
Maximum leverage ratio	55.00%
Minimum common stock outstanding ownership, percentage				50.00%
Letters of credit outstanding, amount			25,100,000					$ 23,500,000
Revolving credit facility			10,000,000.0					15,000,000.0
Remaining borrowing capacity			1,160,000,000
Line of Credit Facility, Outstanding, Extended Maturity Amount	$ 1,125,000,000
Revolving Credit Facility \| Fed Funds Effective Rate Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Revolving Credit Facility \| Specified Eurocurrency Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Mortgage Repurchase Facility \| Warehouse Agreement Borrowings
Line of Credit Facility [Line Items]
Maximum borrowing capacity							$ 75,000,000	150,000,000		$ 75,000,000
Maximum increase to borrowing capacity					$ 50,000,000	$ 100,000,000			$ 75,000,000	$ 75,000,000
Mortgage Repurchase Facility \| Forecast \| Warehouse Agreement Borrowings
Line of Credit Facility [Line Items]
Maximum increase to borrowing capacity		$ 200,000,000
Financial Services Segment
Line of Credit Facility [Line Items]
Mortgage repurchase facility			$ 202,390,000					$ 149,616,000