Label	Element	Value
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	$ 94,983,000
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	496,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	511,176,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	719,000
Adjustment To Additional Paid In Capital, Deferred Tax Adjustment Related To Tax Receivable Agreement	gsky_AdjustmentToAdditionalPaidInCapitalDeferredTaxAdjustmentRelatedToTaxReceivableAgreement	47,129,000
Temporary Equity, Elimination as Part of Reorganization	us-gaap_TemporaryEquityEliminationAsPartofReorganization	413,990,000
Purchases Of Subsidiary Units In Connection With IPO	gsky_PurchasesOfSubsidiaryUnitsInConnectionWithIPO	901,833,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	0
Limited Liability Company (LLC) Members' Equity, Unit-based Compensation	us-gaap_LimitedLiabilityCompanyLLCMembersEquityUnitBasedCompensation	2,132,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	339,000
Temporary Equity, Distributions	gsky_TemporaryEquityDistributions	16,358,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared, Including Temporary Equity	gsky_DistributionMadetoLimitedLiabilityCompanyLLCMemberCashDistributionsDeclaredIncludingTemporaryEquity	111,341,000
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	2,000
Retained Earnings [Member]
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	57,003,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	(79,729,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	38,213,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	5,550,000
Dividends	us-gaap_Dividends	68,000
Additional Paid-in Capital [Member]
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	37,980,000
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	496,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	590,905,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	719,000
Adjustment To Additional Paid In Capital, Deferred Tax Adjustment Related To Tax Receivable Agreement	gsky_AdjustmentToAdditionalPaidInCapitalDeferredTaxAdjustmentRelatedToTaxReceivableAgreement	47,129,000
Purchases Of Subsidiary Units In Connection With IPO	gsky_PurchasesOfSubsidiaryUnitsInConnectionWithIPO	901,833,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	(159,000)
Limited Liability Company (LLC) Members' Equity, Unit-based Compensation	us-gaap_LimitedLiabilityCompanyLLCMembersEquityUnitBasedCompensation	2,132,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	339,000
Noncontrolling Interest, Effect Of Reorganization	gsky_NoncontrollingInterestEffectOfReorganization	69,299,000
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	2,000
Noncontrolling Interest [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	15,657,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	159,000
Noncontrolling Interest, Effect Of Reorganization	gsky_NoncontrollingInterestEffectOfReorganization	(69,299,000)
Dividends	us-gaap_Dividends	14,537,000
Additional Paid In Capital - LLC [Member]
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	(97,344,000)
Common Class A [Member]
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	53,012,000
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	0
Common Class A [Member] | IPO [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	950,990,000
Common Class A [Member] | Other Offering [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	0
Common Class A [Member] | Additional Paid-in Capital [Member]
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	52,988,000
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(1,000)
Common Class A [Member] | Additional Paid-in Capital [Member] | IPO [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	950,553,000
Common Class A [Member] | Additional Paid-in Capital [Member] | Other Offering [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ (4,000)
Common Class A [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised	125,398
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	$ 24,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	158,000
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	$ 1,000
Stock Issued During Period, Shares, Conversion of Units	us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits	15,816,268
Stock Repurchased During Period, Shares	us-gaap_StockRepurchasedDuringPeriodShares	2,426,198
Common Class A [Member] | Common Stock [Member] | IPO [Member]
Stock Issued During Period, Shares, New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	43,700,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 437,000
Common Class A [Member] | Common Stock [Member] | Other Offering [Member]
Stock Issued During Period, Shares, New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	434,782.61
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 4,000
Common Class B [Member]
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 129,000
Common Class B [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues	us-gaap_StockIssuedDuringPeriodSharesNewIssues	128,983,353.2
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 129,000