Equity Method Investment, Board Seats

No definition available.

Name:	grbk_EquityMethodInvestmentBoardSeats
Namespace Prefix:	grbk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Equity Method Investment, Board Seats Held

+ References

No definition available.

+ Details

Name:	grbk_EquityMethodInvestmentBoardSeatsHeld
Namespace Prefix:	grbk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Minimum number of individuals from the Company required to vote for an action to be approved by the board of managers.

+ References

No definition available.

+ Details

Name:	grbk_NumberofIndividualsRequiredtoGiveApprovalofanActiontotheBoardofManagers
Namespace Prefix:	grbk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Ownership Percentage by Parent Included in Consolidation

+ References

No definition available.

+ Details

Name:	grbk_OwnershipPercentagebyParentIncludedinConsolidation
Namespace Prefix:	grbk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of Voting Interest

+ References

No definition available.

+ Details

Name:	grbk_PercentageofVotingInterest
Namespace Prefix:	grbk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DeferredFinanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_Depreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

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

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The net carrying amount as of the balance sheet date of the sum of the various components of an operative builder's inventory, including finished homes. Operative builders primarily consist of entities that develop land, construct residential homes and commercial and industrial buildings thereon, and sell them to home buyers and operators of the commercial and industrial properties.

+ References

+ Details

Name:	us-gaap_InventoryOperativeBuilders
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(a)(4))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30)(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of consolidated variable interest entity's (VIE) assets that do not have to be used to settle obligations of VIE.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5710-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6839525&loc=SL6758485-165988

+ Details

Name:	us-gaap_VariableInterestEntityConsolidatedAssetsNotPledged
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis=us-gaap_CalculatedUnderRevenueGuidanceInEffectBeforeTopic606Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesInventoryAxis=grbk_ModelHomeFurnishingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=grbk_ModelHomeFurnishingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201409Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis=us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=grbk_HomeConstructionContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=grbk_ChallengerHomesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=grbk_ProvidenceTitleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=grbk_GreenBrickMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_CashMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_InventoriesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=grbk_GHOHomesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=grbk_DallasandAtlantaBasedControlledBuildersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=grbk_FloridaBasedControlledBuilderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Basis of Presentation and Significant Accounting Policies (Details)	6 Months Ended
	Jun. 30, 2018 USD ($) segment individual board_seat	Jun. 30, 2017 USD ($)	Apr. 26, 2018	Mar. 31, 2018	Dec. 31, 2017 USD ($)	Aug. 31, 2017
Class of Stock [Line Items]
Assets of VIEs that can be used only to settle obligations of the VIEs	$ 57,800,000				$ 56,100,000
Number of reportable segments \| segment	2
Number of operating segments \| segment	3
Cumulative effect on opening balance of retained earnings	$ 151,975,000				125,903,000
Property and equipment, net	3,454,000				804,000
Inventory	581,368,000				496,054,000
Debt issuance costs	1,105,000				1,227,000
Selling, General and Administrative Expense
Class of Stock [Line Items]
Depreciation expense	800,000
Calculated under Revenue Guidance in Effect before Topic 606 \| Cost of Sales
Class of Stock [Line Items]
Depreciation expense		$ 500,000
Model Home Furnishings \| Calculated under Revenue Guidance in Effect before Topic 606
Class of Stock [Line Items]
Inventory					1,100,000
Model Home Furnishings
Class of Stock [Line Items]
Property and equipment, net	$ 1,800,000
Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606
Class of Stock [Line Items]
Cumulative effect on opening balance of retained earnings					0
Home Construction Contracts
Class of Stock [Line Items]
Intangible asset amortization period	2 years
Challenger Homes
Class of Stock [Line Items]
Ownership percent						49.90%
Providence Title
Class of Stock [Line Items]
Ownership percent				49.00%
Green Brick Mortgage
Class of Stock [Line Items]
Ownership percent	49.00%
Cash
Class of Stock [Line Items]
Assets of VIEs that can be used only to settle obligations of the VIEs	$ 400,000				900,000
Inventories
Class of Stock [Line Items]
Assets of VIEs that can be used only to settle obligations of the VIEs	$ 49,300,000				$ 47,800,000
GHO Homes
Class of Stock [Line Items]
Percent of equity interests acquired			80.00%
Ownership percentage by noncontrolling owners			20.00%
Variable Interest Entity, Primary Beneficiary
Class of Stock [Line Items]
Board seats held \| board_seat	2
Board seats available \| board_seat	3
Number of individuals required to give approval of an action to the board of managers \| individual	1
Variable Interest Entity, Primary Beneficiary \| Dallas and Atlanta Based Controlled Builders
Class of Stock [Line Items]
Ownership percentage by parent	50.00%
Percentage of voting interest	51.00%
Ownership percentage by noncontrolling owners	50.00%
Variable Interest Entity, Primary Beneficiary \| Florida Based Controlled Builder
Class of Stock [Line Items]
Ownership percentage by parent	80.00%
Ownership percentage by noncontrolling owners	20.00%
Variable Interest Entity, Primary Beneficiary \| GHO Homes
Class of Stock [Line Items]
Percent of equity interests acquired	80.00%
Percent required to consolidate within consolidated financial statements	100.00%
Ownership percentage by noncontrolling owners	20.00%