GreenSky (GSKY) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 08, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	GreenSky, Inc.
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	1,712,923
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Common Stock, Shares Outstanding		57,797,385
Entity Emerging Growth Company	true
Entity Small Business	false
Entity Ex Transition Period	true

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash	$ 294,336	$ 224,614
Restricted cash	160,909	129,224
Loan receivables held for sale, net	14,765	73,606
Accounts receivable, net	18,623	18,358
Related party receivables	122	218
Property, equipment and software, net	9,768	7,848
Deferred tax assets, net	297,983	0
Other assets	4,989	9,021
Total assets	801,495	462,889
Liabilities
Accounts payable	6,134	6,845
Accrued compensation and benefits	5,525	7,677
Other accrued expenses	1,013	1,606
Finance charge reversal liability	117,202	94,148
Term loan	387,401	338,263
Tax receivable agreement liability	255,823	0
Related party liabilities	937	1,548
Other liabilities	39,649	38,841
Total liabilities	813,684	488,928
Commitments, Contingencies and Guarantees (Note 12)
Temporary Equity (Note 16)
Redeemable preferred units	0	430,348
Permanent Equity (Deficit)
Additional paid-in capital	11,429	(554,906)
Retained earnings	17,210	98,519
Total permanent equity (deficit)	(12,189)
Limited Liability Company (LLC) Members' Equity, Including Portion Attributable to Noncontrolling Interest		(456,387)
Total liabilities, temporary and permanent equity (deficit)	801,495	$ 462,889
Class A common stock, par value $0.01 and 57,797,385 shares issued and outstanding at September 30, 2018 and 0 shares issued and outstanding at December 31, 2017
Permanent Equity (Deficit)
Permanent equity	576
Class B common stock, par value $0.001 and 128,826,614 shares issued and outstanding at September 30, 2018 and 0 shares issued and outstanding at December 31, 2017
Permanent Equity (Deficit)
Permanent equity	$ 129

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Class A common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	57,797,385	0
Common stock, outstanding (in shares)	57,797,385	0
Class B common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, issued (in shares)	128,826,614	0
Common stock, outstanding (in shares)	128,826,614	0

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue
Total revenue		$ 113,912	$ 88,316	$ 304,942	$ 236,073
Costs and expenses
Cost of revenue (exclusive of depreciation and amortization shown separately below)		35,374	22,036	105,269	68,528
Compensation and benefits		14,326	14,880	46,254	40,477
Sales and marketing		975	328	2,841	900
Property, office and technology		3,792	2,752	9,651	8,032
Depreciation and amortization		1,192	923	3,229	2,798
General and administrative		3,132	4,225	11,379	12,231
Related party expenses		864	3,080	1,677	4,084
Total costs and expenses		59,655	48,224	180,300	137,050
Operating profit		54,257	40,092	124,642	99,023
Other income/(expense), net
Interest income		1,912	1,627	4,714	4,158
Interest expense		(6,013)	(2,189)	(17,391)	(2,363)
Other gains/(losses)		(1,069)	(1,368)	(1,864)	(2,052)
Total other income/(expense), net		(5,170)	(1,930)	(14,541)	(257)
Income before income tax expense		49,087	38,162	110,101	98,766
Income tax expense		3,375	0	4,969	0
Net income		45,712	38,162	105,132	98,766
Less: Net income attributable to noncontrolling interests		33,711		87,581
Net income attributable to GreenSky, Inc.		$ 12,001		$ 17,551
Earnings per share of Class A common stock
Basic (in dollars per share)	[1]	$ 0.21		$ 0.31
Diluted (in dollars per share)	[1]	$ 0.20		$ 0.30
Transaction fees
Revenue
Total revenue		$ 96,770	76,170	$ 257,907	202,543
Servicing and other
Revenue
Total revenue		$ 17,142	$ 12,146	$ 47,035	$ 33,530
[1]	Basic and diluted earnings per share of Class A common stock is applicable only for the period from May 24, 2018 through September 30, 2018, which is the period following the initial public offering ("IPO") and related Reorganization Transactions (as defined in Note 1 to the Unaudited Consolidated Financial Statements). See Note 2, Earnings per Share, for the number of shares used in the computation of earnings per share of Class A common stock and the basis for the computation of earnings per share.

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) Statement - USD ($) $ in Thousands	Total	Additional Paid-in Capital	Retained Earnings	Noncontrolling Interest	Class A common stock	Class A common stockCommon stock	Class B common stock	Class B common stockCommon stock
Members' equity, beginning balance at Dec. 31, 2016	$ (123,510)	$ (283,529)	$ 160,019
Increase (Decrease) in Stockholders' Equity
Net income	98,766		98,766
Repurchases	(249)	(249)
Share-based compensation prior to Reorganization Transactions	3,032	3,032
Distributions prior to Reorganization Transactions	(351,808)	(275,197)	(76,611)
Equity-based payments to non-employees prior to Reorganization Transactions	297	297
Class A stock option exercises (in shares)					202,000
Class A common stock option exercises in connection with IPO	15	15
Members' equity, ending balance at Sep. 30, 2017	(373,457)	(555,631)	182,174
Redeemable preferred units at Dec. 31, 2016	335,720
Increase (Decrease) in Temporary Equity
Distributions prior to Reorganization Transactions	(63,353)
Redeemable preferred units at Sep. 30, 2017	272,367
Beginning Balance at Dec. 31, 2016	212,210
Increase (Decrease) In Permanent Equity And Temporary Equity [Roll Forward]
Distributions prior to Reorganization Transactions	(415,161)
Ending Balance at Sep. 30, 2017	(101,090)
Members' equity, beginning balance at Dec. 31, 2017	(456,387)	(554,906)	98,519
Beginning balance (in shares) at Dec. 31, 2017					0		0
Increase (Decrease) in Stockholders' Equity
Net income	105,132
Ending balance (in shares) at Sep. 30, 2018					57,797,385	57,797,385	128,826,614	128,826,614
Ending balance at Sep. 30, 2018	(12,189)	$ 11,429	$ 17,210	$ (41,533)		$ 576		$ 129
Redeemable preferred units at Dec. 31, 2017	430,348
Redeemable preferred units at Sep. 30, 2018	0
Beginning Balance at Dec. 31, 2017	$ (26,039)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 105,132,000	$ 98,766,000
Adjustments to reconcile net income to net cash provided by/(used in) operating activities
Depreciation and amortization	3,229,000	2,798,000
Provision for bad debt expense	1,367,000	802,000
Share-based compensation expense	4,304,000	3,032,000
Equity-based payments to non-employees	12,000	297,000
Impairment losses	0	78,000
Non-cash rent expense	(293,000)	(283,000)
Amortization of debt related costs	1,262,000	270,000
Loss on extinguishment of debt	0	254,000
Fair value change in assets and liabilities	621,000	800,000
Original issuance discount on term loan payment	(20,000)	0
Deferred tax expense	4,969,000	0
Changes in assets and liabilities:
(Increase)/decrease in loan receivables held for sale	58,731,000	(63,582,000)
(Increase)/decrease in accounts receivable	(1,521,000)	(646,000)
(Increase)/decrease in related party receivables	96,000	156,000
(Increase)/decrease in other assets	4,032,000	(1,031,000)
Increase/(decrease) in accounts payable	(711,000)	2,037,000
Increase/(decrease) in finance charge reversal liability	23,054,000	14,688,000
Increase/(decrease) in related party liabilities	(933,000)	(645,000)
Increase/(decrease) in other liabilities	90,000	9,794,000
Net cash provided by operating activities	203,421,000	67,585,000
Cash flows from investing activities
Purchases of property, equipment and software	(4,849,000)	(2,575,000)
Net cash used in investing activities	(4,849,000)	(2,575,000)
Cash flows from financing activities
Proceeds from IPO, net of underwriters discount and commissions	954,845,000	0
Purchases of GreenSky Holdings, LLC units	(901,833,000)	0
Purchases of Class A common stock	(53,012,000)	0
Issuances of Class B common stock	129,000	0
Redemptions of GreenSky Holdings, LLC units prior to Reorganization Transactions	(496,000)	(249,000)
Proceeds from term loan	399,000,000	346,500,000
Repayments of term loan	(351,105,000)	0
Member distributions	(141,019,000)	(405,653,000)
Option and warrant exercises prior to Reorganization Transactions	339,000	15,000
Payment of equity transaction expenses prior to Reorganization Transactions	(32,000)	0
Payment of tax withholdings upon option exercises after Reorganization Transactions	(126,000)	0
Payment of IPO related expenses	(3,855,000)	0
Payment of debt issuance costs	0	(8,155,000)
Net cash used in financing activities	(97,165,000)	(67,542,000)
Net increase/(decrease) in cash and restricted cash	101,407,000	(2,532,000)
Cash and restricted cash at beginning of period	353,838,000	228,114,000
Cash and restricted cash at end of period	455,245,000	225,582,000
Supplemental non-cash investing and financing activities
Leasehold improvements acquired but not paid	300,000	0
Distributions accrued but not paid	$ 10,887,000	$ 9,508,000

Organization, Summary of Signif

Organization, Summary of Signifant Accounting Policies and New Accounting Standards	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Basis of Presentation and New Accounting Standards	Organization, Summary of Significant Accounting Policies and New Accounting Standards Organization GreenSky, Inc. (or the "Company," "we" or "our") was formed as a Delaware corporation on July 12, 2017. The Company was formed for the purpose of completing an IPO of its Class A common stock and certain Reorganization Transactions, as further described below, in order to carry on the business of GreenSky Holdings, LLC (“GS Holdings”) and its consolidated subsidiaries. GS Holdings, a holding company with no operating assets or operations, was organized in August 2017. On August 24, 2017, GS Holdings acquired a controlling interest in GreenSky, LLC ("GSLLC"), a Georgia limited liability company, which is an operating entity. Common membership interests of GS Holdings are referred to as "Holdco Units." Immediately prior to our IPO, (i) the operating agreement of GS Holdings (the "GS Holdings Agreement") was amended and restated to, among other things, modify its capital structure by replacing the different classes of membership interests and profits interests with Holdco Units; (ii) we issued to each of the Continuing LLC Members (as defined below) a number of shares of GreenSky, Inc. Class B common stock equal to the number of Holdco Units held by it (other than the Holdco Units that were exchanged in connection with the IPO), for consideration in the amount of $0.001 per share of Class B common stock; (iii) certain Holdco Units were contributed to GreenSky, Inc. in exchange for shares of our Class A common stock; (iv) equity holders of the Former Corporate Investors (as defined below) contributed their equity in the Former Corporate Investors to GreenSky, Inc. in exchange for shares of our Class A common stock and the right to certain payments under the Tax Receivable Agreement (“TRA”), and Former Corporate Investors merged with and into subsidiaries of GreenSky, Inc.; (v) outstanding options to acquire Class A units of GS Holdings were equitably adjusted so that they are exercisable for shares of Class A common stock; and (vi) outstanding warrants to acquire Class A units of GS Holdings were equitably adjusted pursuant to their terms so that they are exercisable for Holdco Units (and an equal number of shares of Class B common stock). We refer to these transactions collectively as the “Reorganization Transactions.” The Reorganization Transactions are more fully described in our final IPO prospectus dated May 23, 2018 filed with the United States Securities and Exchange Commission on May 25, 2018 (the "Final IPO Prospectus"). Following the Reorganization Transactions, the Original GS Equity Owners (other than the Former Corporate Investors) and certain Original Profits Interests Holders, which we collectively refer to as the "Continuing LLC Members," continue to own Holdco Units. Original GS Equity Owners refers to the owners of units of GS Holdings prior to the Reorganization Transactions. Former Corporate Investors refers to certain of the Original GS Equity Owners that merged with and into one or more subsidiaries of GreenSky, Inc. in connection with the Reorganization Transactions, which was accounted for as a common control transaction and had no material impact on the net assets of the Company. Original Profits Interests Holders refers to the owners of profits interests in GS Holdings prior to the Reorganization Transactions. On May 24, 2018, the Company's Class A common stock commenced trading on the NASDAQ Stock Market in connection with its IPO of 43,700,000 shares of its Class A common stock at a public offering price of $23.00 per share, receiving approximately $954.8 million in net proceeds, after deducting underwriting discounts and commissions (but not including other offering costs), which were used to purchase 2,426,198 shares of Class A common stock and 41,273,802 newly-issued GS Holdings common units at a price per unit equal to the price per share of Class A common stock sold in the IPO, less underwriting discounts and commissions. The newly-issued GS Holdings common units were sold by Continuing LLC Members, which we also refer to as "Exchanging Members." Pursuant to an "Exchange Agreement," the Exchanging Members can exchange their Holdco Units (with automatic cancellation of an equal number of shares of Class B common stock) for shares of our Class A common stock on a one -for-one basis, subject to customary adjustments, or for cash (based on the market price of the shares of Class A common stock), at our option (such determination to be made by the disinterested members of our board of directors). The IPO and Reorganization Transactions resulted in the Company becoming the sole managing member of GS Holdings. As the sole managing member of GS Holdings, we operate and control all of GS Holdings’ operations and, through GS Holdings and its subsidiaries, conduct GS Holdings’ business. As of September 30, 2018 , the Company had an economic interest in GS Holdings of 31.3% , after adjusting for unvested units. The Company consolidates the financial results of GS Holdings and reports a noncontrolling interest in its Unaudited Consolidated Financial Statements representing the GS Holdings interests held by Continuing LLC Members. Summary of Significant Accounting Policies Basis of Presentation The balance sheet data as of December 31, 2017 was derived from the audited Consolidated Financial Statements included in our Final IPO Prospectus. The Unaudited Consolidated Financial Statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission for interim financial statements. Accordingly, the Unaudited Consolidated Financial Statements do not include all information and disclosures required by accounting principles generally accepted in the United States that would be required for complete financial statements. In the opinion of management, the Unaudited Consolidated Financial Statements reflect all adjustments, which are of a normal recurring nature, necessary for a fair statement of our statements of operations for the three and nine months ended September 30, 2018 and 2017 , our balance sheets at September 30, 2018 and December 31, 2017 , and our cash flows for the nine months ended September 30, 2018 and 2017 . We condensed or omitted certain notes and other information from the interim financial statements presented in this Quarterly Report on Form 10-Q. Therefore, these interim statements should be read in conjunction with our Final IPO Prospectus. The results for the three and nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the full year. See Note 1 to the audited Consolidated Financial Statements included in our Final IPO Prospectus for additional information about our significant accounting policies. Use of Estimates The preparation of financial statements in conformity with United States generally accepted accounting principles ("GAAP") requires that management make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Such estimates and assumptions include, but are not limited to, those that relate to fair value measurements, share-based compensation and income taxes. In developing estimates and assumptions, management uses all available information; however, actual results could materially differ from those estimates and assumptions. Cash and Restricted Cash The following table provides a reconciliation of cash and restricted cash reported within the Unaudited Consolidated Balance Sheets to the total included within the Unaudited Consolidated Statements of Cash Flows as of the periods indicated. September 30, 2018 September 30, 2017 Cash $ 294,336 $ 105,293 Restricted cash 160,909 120,289 Cash and restricted cash in Unaudited Consolidated Statements of Cash Flows $ 455,245 $ 225,582 Recently Adopted Accounting Standards Revenue from contracts with customers In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-09 to clarify the principles for recognizing revenue and to develop a common revenue standard, which is codified in ASC 606, Revenue from Contracts with Customers . Under this new standard, an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The FASB also issued several updates to ASU 2014-09. We elected to early adopt this standard and to apply its provisions as of January 1, 2017 to all open contracts existing as of that date using the modified retrospective approach. We determined that the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings was immaterial. Further, our adoption of the new standard did not have a material impact on any balance sheet or income statement line items in the period of adoption and, as such, we did not record any adjustments to the consolidated financial statements related to our adoption of this standard. Disaggregated revenue Revenue disaggregated by type of service was as follows for the periods presented: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Merchant fees $ 82,909 $ 63,934 $ 217,850 $ 169,702 Interchange fees 13,861 12,236 40,057 32,841 Transaction fees 96,770 76,170 257,907 202,543 Servicing fees 17,101 12,071 46,890 33,245 Other (1) 41 75 145 285 Servicing and other 17,142 12,146 47,035 33,530 Total revenue $ 113,912 $ 88,316 $ 304,942 $ 236,073 (1) Other revenue includes miscellaneous revenue items that are individually immaterial. Other revenue is presented separately herein in order to clearly present merchant, interchange and servicing fees, which are more integral to our primary operations and better enable financial statement users to calculate metrics such as servicing and merchant fee yields. We have no remaining performance obligations as of September 30, 2018 . No assets were recognized from the costs to obtain or fulfill a contract with a customer as of September 30, 2018 or December 31, 2017 . Recognition and measurement of financial assets and financial liabilities In January 2016, the FASB issued ASU 2016-01 to address certain aspects of recognition, measurement, presentation and disclosure of financial instruments. We adopted the standard for the reporting period beginning January 1, 2018. As a result of adopting the standard, we eliminated the disclosure requirement of the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet, which applies to our fair value of term loan disclosure in Note 3. The remaining provisions of the standard were either not applicable to us or already satisfied in our disclosures. Therefore, our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Improvements to employee share-based payment accounting In March 2016, the FASB issued ASU 2016-09 to simplify certain aspects of the accounting for share-based payment transactions. Under the new standard, all excess tax benefits and tax deficiencies should be recognized as income tax benefit or expense, respectively, in the income statement when stock awards vest or are settled. In addition, the standard eliminates the requirement to reclassify cash flows related to excess tax benefits from operating activities to financing activities on the statements of cash flows, increases the threshold for withholding an employee’s vested shares for tax withholding purposes without triggering liability accounting and clarifies that cash payments made by an employer to tax authorities on an employee’s behalf when directly withholding shares for tax withholding purposes should be presented as a financing activity on the statement of cash flows. The standard also provides an accounting policy election to account for forfeitures as they occur rather than to estimate the number of awards that are expected to vest. We adopted the standard for the reporting period beginning January 1, 2017. The provisions related to excess tax benefits or deficiencies from share-based award activity became applicable for us following the IPO and Reorganization Transactions. We also elected to retain our existing accounting policy election to estimate award forfeitures. Our adoption of this standard did not have a material impact on our Unaudited Consolidated Financial Statements. Scope of modification accounting In May 2017, the FASB issued ASU 2017-09 to provide clarity and reduce both diversity in practice and the cost and complexity to an entity when applying the guidance in ASC 718, Compensation—Stock Compensation, to a change in the terms or conditions of a share-based payment award. The standard provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. We adopted the standard for the reporting period beginning January 1, 2018, and will apply its provisions prospectively to any award modified on or after the adoption date. Our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Disclosure framework - changes to the disclosure requirements for fair value measurement In August 2018, the FASB issued ASU 2018-13 to modify certain disclosure requirements about recurring and nonrecurring fair value measurements to improve disclosure effectiveness. We adopted the standard for the reporting period beginning July 1, 2018. As a result of adopting this standard, we replaced our previously disclosed quantitative sensitivity analyses for unobservable inputs used to develop our Level 3 fair value measurements with narrative descriptions of the uncertainty of our fair value measurements to changes in unobservable inputs, and added explanations of how we calculated the weighted averages of the significant unobservable inputs used to develop our Level 3 fair value measurements. Our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Accounting Standards Issued, But Not Yet Adopted Leases In February 2016, the FASB issued ASU 2016-02, which requires lessees to recognize leases with terms greater than twelve months on the balance sheet as right-of-use assets and corresponding liabilities. Lessees will continue to classify leases as either operating leases, using a straight-line expense pattern, or financing leases, using a front-loaded expense pattern. The standard also requires enhanced quantitative and qualitative disclosures related to the lease arrangements. The standard is effective for us on January 1, 2019, with early adoption permitted, using a modified retrospective approach. We are evaluating the potential impact of adopting this standard by reviewing our existing lease contracts, all of which are operating leases wherein the Company is the lessee. For the future minimum lease payments of $16.8 million as of September 30, 2018 required under our existing operating leases (as disclosed in Note 12) and for other similar leases we may enter into prior to adopting this standard, we expect to gross up our Unaudited Consolidated Balance Sheets at their present values to recognize the right-of-use assets and lease liabilities. The quantitative impact of adopting this standard remains under evaluation; however, we do not expect material changes to the recognition, measurement and presentation of rent expense, which is included within property, office and technology expenses and related party expenses in our Unaudited Consolidated Statements of Operations. Similarly, we do not expect a material impact to our Unaudited Consolidated Statements of Cash Flows. In July 2018, the FASB issued ASU 2018-10, which clarifies certain aspects of the guidance issued in ASU 2016-02. Upon adoption of this standard, we, as the lessee, will be required to reassess lease classification upon modification based on the facts and circumstances and the modified terms and conditions, if applicable, as of the date of reassessment. The remaining provisions of the standard are either not applicable to us or already satisfied in our disclosures. The standard is effective for us on January 1, 2019, with early adoption permitted, using a modified retrospective approach. We are currently evaluating the potential impact of adopting this standard; however, we do not expect material changes to the classification of leases or to the recognition of rent expense. In July 2018, the FASB issued ASU 2018-11, which provides an additional (and optional) transition method to adopt ASU 2016-02 by applying its provisions at the adoption date and recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, rather than applying the provisions of ASU 2016-02 at the beginning of the earliest period presented in the financial statements. Entities that elect this additional transition method must provide the required ASC 840, Leases , disclosures for all periods that continue to be in accordance with ASC 840. The remaining provisions of the standard are not applicable to us, as the provisions relate only to lessors. The standard is effective for us on January 1, 2019 in conjunction with our adoption of ASU 2016-02. Measurement of credit losses on financial instruments In June 2016, the FASB issued ASU 2016-13, which is intended to better align the timing of recognition of credit losses on financial instruments with management’s expectations. The standard requires a financial asset (or group of financial assets) measured at amortized cost to be presented at the net amount expected to be collected. Management must determine expected credit losses for all financial instruments held at the reporting date based on relevant information about past events, including historical experience, current conditions and reasonable and supportable forecasts, the latter of which broadens current guidance. The standard requires enhanced disclosures to help investors and other financial statement users to better understand the significant estimates and judgments used in estimating credit losses. The standard is effective for us on January 1, 2020, with early adoption permitted, but not before January 1, 2019. The majority of this standard's provisions must be applied using a modified retrospective approach. We are currently evaluating the potential impact of adopting this standard. Improvements to nonemployee share-based payment accounting In June 2018, the FASB issued ASU 2018-07 to simplify certain aspects of the accounting for non-employee share-based payment transactions. Under the new standard, all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor's own operations by issuing share-based payment awards are within the scope of ASC 718. Consistent with the accounting requirement for employee share-based payment awards, non-employee share-based payment awards within the scope of ASC 718 are measured at grant-date fair value of the equity instruments, and the requirement to reassess classification of non-employee share-based payment awards upon vesting is eliminated. The standard is effective for us on January 1, 2019, with early adoption permitted, using a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption to remeasure equity-classified awards for which a measurement date has not been established and liability-classified awards that have not been settled by the date of adoption. We are currently evaluating the potential impact of adopting this standard; however, we do not expect adoption to have a material impact, as the Company has a limited number of non-employee share-based payment transactions outstanding and does not anticipate material non-employee share-based payment transactions in the future. Customer's accounting for implementation costs incurred in a cloud computing arrangement that is a service contract In August 2018, the FASB issued ASU 2018-15, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Accordingly, costs for implementation activities in the application development stage are capitalized depending on the nature of the costs, while costs incurred during the preliminary project and post-implementation stages are expensed as the activities are performed. This standard also requires entities to amortize the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement and to apply the existing impairment guidance in ASC 350-40 to the capitalized implementation costs as if the costs were long-lived assets. The standard clarifies that such capitalized implementation costs are also subject to the guidance on abandonment in ASC 360, Property, Plant, and Equipment . In addition, this standard requires alignment in presentation between: (1) the expense related to the capitalized implementation costs and the fees associated with the hosting element (service) of the arrangement on the statement of operations, (2) the capitalized implementation costs and any prepayment for the fees of the associated hosting arrangement on the balance sheet, and (3) the payments for capitalized implementation costs and the payments made for fees associated with the hosting element in the statement of cash flows. The standard is effective for us on January 1, 2020, with early adoption permitted, and should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. We are refining our inventory of existing cloud computing arrangements to identify hosting arrangements that are service contracts and will evaluate how to account for the implementation costs of such arrangements.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic earnings per share of Class A common stock is computed by dividing net income attributable to GreenSky, Inc. by the weighted average number of shares of Class A common stock outstanding during the period. Diluted earnings per share of Class A common stock is computed by dividing net income attributable to GreenSky, Inc., adjusted for the assumed exchange of all potentially dilutive Holdco Units for Class A common stock, by the weighted average number of shares of Class A common stock outstanding adjusted to give effect to potentially dilutive elements. Prior to the IPO, the GS Holdings membership structure included Class A, B, and C Units and Profits Interests. The Company analyzed the calculation of earnings per unit for periods prior to the IPO and determined that it resulted in values that would not be meaningful to the users of these Unaudited Consolidated Financial Statements. Therefore, earnings per share information has not been presented for the three and nine months ended September 30, 2017 . The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for the three and nine months ended September 30, 2018 . The basic and diluted earnings per share for the nine months ended September 30, 2018 represents only the period from May 24, 2018 to September 30, 2018 , the period wherein we had outstanding Class A common stock. Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 Numerator: Income before income tax expense $ 49,087 $ 110,101 Less: Net income attributable to GS Holdings prior to the Reorganization Transactions — 38,213 Less: Net income attributable to noncontrolling interests subsequent to the Reorganization Transactions 33,711 49,368 Less: Income tax expense 3,375 4,969 Net income attributable to GreenSky, Inc. - basic $ 12,001 $ 17,551 Add: Reallocation of net income attributable to noncontrolling interests after the Reorganization Transactions from the assumed exchange of common units of GS Holdings for Class A common stock 33,711 49,368 Less: Income tax expense on reallocation of net income attributable to noncontrolling interests (1) 7,400 10,893 Net income attributable to GreenSky, Inc. - diluted $ 38,312 $ 56,026 Denominator: Weighted average shares of Class A common stock outstanding - basic 57,412,673 57,408,861 Add: Dilutive effects as shown separately below Holdco Units exchangeable for Class A common stock 128,052,758 128,155,169 Class A common stock options 2,813,764 2,646,827 Holdco warrants exchangeable for Class A common stock 707,414 635,436 Unvested Class A common stock (2) 169,315 179,339 Weighted average shares of Class A common stock outstanding - diluted 189,155,924 189,025,632 Earnings per share of Class A common stock outstanding - basic $ 0.21 $ 0.31 Earnings per share of Class A common stock outstanding - diluted (3)(4) $ 0.20 $ 0.30 (1) For the three and nine months ended September 30, 2018 periods, we assumed effective tax rates of 22.0% and 22.1% , respectively. (2) Includes both Class A common stock issued as part of the Reorganization Transactions and unvested Class A common stock awards issued subsequent to the Reorganization Transactions. (3) Year-to-date results do not agree to the sum of individual quarter-to-date results due to rounding. (4) Our calculation of diluted earnings per share excludes 1,184,029 Class A common stock options and 134,170 unvested Class A common stock awards for the three and nine months ended September 30, 2018 , as their inclusion would have been anti-dilutive. These amounts represent the number of instruments outstanding at the end of the period. Application of the treasury stock method would reduce these amounts if they had a dilutive effect and were included in the computation of diluted earnings per share.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities We have financial assets and liabilities subject to fair value measurement, which include our loan receivables held for sale, finance charge reversal ("FCR") liability and servicing liabilities associated with transfers of rights to previously charged-off loan receivables ("Charged-Off Receivables"). We apply the market approach, which uses observable prices and other relevant information that is generated by market transactions involving identical or comparable assets or liabilities, to value our loan receivables held for sale and the income approach, which uses valuation techniques to convert future amounts to a single, discounted present value amount, to value our FCR liability and servicing liabilities. Loan receivables held for sale Loan receivables held for sale are recorded in the Unaudited Consolidated Balance Sheets at the lower of cost or fair value and, therefore, are measured at fair value on a nonrecurring basis. For our loan receivables held for sale, fair value approximates par value, as we have consistently sold loans for the full current balance in historical and current period transactions with federally insured banks that originate loans under the GreenSky program and any other lenders with respect to those loans (referred to henceforth as "Bank Partners"). Loan receivables held for sale are classified within Level 2 of the fair value hierarchy, as the primary component of the price is obtained from observable values of loan receivables with similar terms and characteristics sold to our Bank Partners. We have the ability to access this market, and it is the market into which these loan receivables are typically sold. Refer to Note 4 for additional information on our loan receivables held for sale. Finance charge reversals Our Bank Partners offer certain loan products that have a feature whereby the account holder is provided a promotional period to repay the loan principal balance in full without incurring a finance charge. For these loan products, we bill interest each month throughout the promotional period and, under the terms of the contracts with our Bank Partners, we are obligated to pay this billed interest to the Bank Partners if an account holder pays off the loan balance in full within the promotional period. Therefore, the monthly process of billing interest on deferred loan products triggers a potential future FCR liability for the Company. The FCR component of our Bank Partner contracts qualifies as an embedded derivative. The FCR liability is carried at fair value on a recurring basis in the Unaudited Consolidated Balance Sheets and is estimated based on historical experience and management’s expectation of future FCR. The FCR liability is classified within Level 3 of the fair value hierarchy, as the primary component of the fair value is obtained from unobservable inputs based on the Company’s data, reasonably adjusted for assumptions that would be used by market participants. The FCR liability is not designated as a hedge for accounting purposes and, as such, changes in its fair value are recorded within cost of revenue in the Unaudited Consolidated Statements of Operations. Charged-off receivables Periodically, we transfer our rights to certain Charged-Off Receivables in exchange for a cash payment based on the expected recovery rate of such loan receivables, which consist primarily of previously charged-off Bank Partner loans. We have no continuing involvement with these Charged-Off Receivables other than performing reasonable servicing and collection efforts on behalf of the third parties and Bank Partners that purchased the Charged-Off Receivables. The proceeds from transfers of Charged-Off Receivables attributable to Bank Partner loans are recognized on a collected basis as reductions to cost of revenue, which reduces the fair value adjustment to the FCR liability in the period of transfer. The following table presents details of Charged-Off Receivables transfers during the periods indicated. Aggregate Unpaid Balance Proceeds Bank Partner loans Loan receivables held for sale Total (1) Bank Partner loans Loan receivables held for sale Total Three months ended September 30, 2018 $ 67,455 $ 841 $ 68,296 $ 9,039 $ 113 $ 9,152 Three months ended September 30, 2017 73,494 1,061 74,555 5,914 86 6,000 Nine months ended September 30, 2018 142,350 2,124 144,474 19,039 284 19,323 Nine months ended September 30, 2017 73,494 1,061 74,555 5,914 86 6,000 (1) During the three and nine months ended September 30, 2018 , $3,952 and $10,632 , respectively, of the aggregate unpaid balance on cumulative transferred Charged-Off Receivables were recovered through our servicing efforts on behalf of our Charged-Off Receivables investors. During the three and nine months ended September 30, 2017 , such recoveries totaled $498 and $498 , respectively. Financial guarantee Under the terms of the contracts with our Bank Partners, we provide limited protection in the event of excessive Bank Partner portfolio credit losses and record a financial guarantee liability at fair value based on historical experience and the amount of current customer delinquencies expected to convert into Bank Partner portfolio credit losses. Refer to Note 12 for additional information. Servicing liabilities We elected the fair value method to account for our servicing liabilities to more appropriately reflect the value of the obligation in the consolidated financial statements. As a result of this election, our servicing liabilities are carried at fair value on a recurring basis within other liabilities in the Unaudited Consolidated Balance Sheets and are estimated using a discounted cash flow model. Servicing liabilities are classified within Level 3 of the fair value hierarchy, as the primary component of the fair value is obtained from unobservable inputs based on peer market data, reasonably adjusted for assumptions that would be used by market participants to service our transferred Charged-Off Receivables portfolios, for which market data is not available. Changes in the fair value of our servicing liabilities are recorded within other gains/(losses) in the Unaudited Consolidated Statements of Operations. The following table summarizes, by level within the fair value hierarchy, the carrying amounts and estimated fair values of our assets and liabilities measured at fair value on a recurring or nonrecurring basis or disclosed, but not carried, at fair value in the Unaudited Consolidated Balance Sheets as of the dates presented. There were no transfers into, out of, or between levels within the fair value hierarchy during any of the periods presented. Refer to Note 4, Note 7 and Note 8 for additional information on these assets and liabilities. Level September 30, 2018 December 31, 2017 Carrying Fair Value Carrying Value Fair Value Assets: Loan receivables held for sale, net (1) 2 $ 14,765 $ 15,459 $ 73,606 $ 74,190 Liabilities: Finance charge reversal liability (2) 3 $ 117,202 $ 117,202 $ 94,148 $ 94,148 Servicing liabilities (2) 3 2,692 2,692 2,071 2,071 Term loan (3) 2 387,401 397,073 338,263 345,820 (1) Measured at fair value on a nonrecurring basis. (2) Measured at fair value on a recurring basis. Servicing liabilities are presented within other liabilities in the Unaudited Consolidated Balance Sheets. The cash flow impacts of our liabilities that are measured at fair value on a recurring basis are included within net cash provided by operating activities in the Unaudited Consolidated Statements of Cash Flows. (3) Disclosed, but not carried, at fair value. The amounts disclosed as of September 30, 2018 relate to the modified term loan and amounts disclosed as of December 31, 2017 relate to the original term loan. Refer to Note 7 for additional information. The carrying value of our term loan is net of unamortized debt discount and debt issuance costs. The fair value of our term loan was determined using a discounted cash flow model based on observable market factors (such as changes in credit spreads for comparable benchmark companies) and credit factors specific to us. Finance charge reversals The following table reconciles the beginning and ending fair value measurements of our FCR liability, which is classified as Level 3 within the fair value hierarchy due to the use of unobservable inputs, during the periods indicated. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 107,047 $ 76,319 $ 94,148 $ 68,064 Receipts (1) 38,520 30,675 100,355 75,014 Settlements (2) (47,211 ) (33,830 ) (136,883 ) (95,363 ) Fair value changes recognized in cost of revenue (3) 18,846 9,588 59,582 35,037 Ending balance $ 117,202 $ 82,752 $ 117,202 $ 82,752 (1) Represents cash received from deferred payment loans during the promotional period (incentive payments), as well as the proceeds received from transferring our rights to Charged-Off Receivables attributable to previously charged-off Bank Partner loans. We consider all monthly incentive payments from Bank Partners during the period to be related to billed finance charges on deferred interest products until monthly incentive payments exceed total billed finance charges on deferred products, which did not occur during any of the periods presented. (2) Represents the reversal of previously billed finance charges associated with deferred payment loan principal balances that paid off within the promotional period. (3) A fair value adjustment is made based on the expected reversal percentage of billed finance charges (expected settlements), which is estimated at each reporting period. The fair value adjustment is recognized in cost of revenue in the Unaudited Consolidated Statements of Operations. The following table presents the estimated reversal rate for billed interest on deferred loan products, which is the significant unobservable input used to value the Level 3 FCR liability, as of the dates indicated. Reversal rate September 30, 2018 December 31, 2017 Range 80.5% – 98.0% 85.5% – 98.0% Weighted average 88.9 % 89.0 % As of September 30, 2018 and December 31, 2017 , we estimated reversal rates depending on the length of the interest-free promotional period (less than 12 months, 18 months and 24 months) and whether or not loan principal payments were required to be paid during the interest-free promotional period. We made the loan principal payment distinction for the 24-month promotional product as of both reporting dates, and for all interest-free promotional periods as of September 30, 2018 . The weighted averages in the above table were calculated by first determining the percentage of the reporting date FCR liability attributable to each of the product groups noted above. We then multiplied these weights by the unique reversal rate for each product group and summed the resulting products. A significant increase or decrease in the estimated reversal rates could result in a significantly higher or lower, respectively, calculation of our expected future payments to our Bank Partners, resulting in a higher or lower, respectively, fair value measurement of our FCR liability as of September 30, 2018 and December 31, 2017 . Servicing liabilities Significant assumptions used in valuing our servicing liabilities were as follows: • Cost of servicing: The cost of servicing represents the servicing rate a willing market participant would require to service loans with similar characteristics as the Charged-Off Receivables. • Discount rate: The discount rate reflects the time value of money adjusted for a risk premium and is within an observable range based on peer market data. • Recovery period: Our recovery period was determined based on a reasonable recovery period for loans of these sizes and characteristics based on historical experience. We assumed that collection efforts for these loans will cease after five years, and the run-off of the portfolio will follow a straight-line methodology, adjusted for actual cash recoveries over time. The following table reconciles the beginning and ending fair value measurements of our servicing liabilities associated with transferring our rights to Charged-Off Receivables, which are classified as Level 3 within the fair value hierarchy due to the use of unobservable inputs, during the periods presented. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 2,272 $ — $ 2,071 $ — Initial obligation from transfer of Charged-Off Receivables (1) 826 886 1,737 886 Fair value changes recognized in other gains/(losses) Change in inputs or assumptions used in the valuation model — — — — Other changes in fair value (1)(2) (406 ) (86 ) (1,116 ) (86 ) Ending balance $ 2,692 $ 800 $ 2,692 $ 800 (1) Recognized in other gains/(losses) in the Unaudited Consolidated Statements of Operations. (2) Represents the reduction of our servicing liability due to the passage of time and collection of loan payments. The following table presents quantitative information about the significant unobservable inputs used to value the Level 3 servicing liabilities as of the dates presented. Input September 30, 2018 December 31, 2017 Range Weighted Average Range Weighted Average Cost of servicing (basis points) 62.5 62.5 62.5 62.5 Discount rate 18.0 % 18.0 % 18.0 % 18.0 % Recovery period (years) 3.8 – 4.9 4.4 4.6 – 4.9 4.8 The recovery period is weighted by the unpaid balance of previously transferred Charged-Off Receivables as of September 30, 2018 and December 31, 2017 . The recovery period reflects the length of time over which we expect to perform servicing activities and has an inverse correlation with the amount by which the servicing liability is reduced each reporting period. As such, a significant increase or decrease in the expected recovery period could have resulted in a higher or lower, respectively, servicing liability as of September 30, 2018 and December 31, 2017 . A significant increase or decrease in the market cost of servicing could have resulted in a significantly higher or lower, respectively, servicing liability as of September 30, 2018 and December 31, 2017 . We only use one cost of servicing assumption; therefore, the weighted average only includes a singular basis points cost of servicing. Finally, a significant increase or decrease in the discount rate could have resulted in a lower or higher, respectively, servicing liability as of September 30, 2018 and December 31, 2017 . The discount rate impact on our servicing liability is much less compared to the recovery period and cost of servicing assumptions. We only use one discount rate assumption; therefore, the weighted average only includes a singular discount rate.

Loan Receivables Held for Sale

Loan Receivables Held for Sale	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loan Receivables Held for Sale	Loan Receivables Held for Sale The following table summarizes the activity in the balance of loan receivables held for sale at lower of cost or fair value during the periods indicated. Nine Months Ended 2018 2017 Beginning balance $ 73,606 $ 41,268 Additions 70,805 104,573 Proceeds from sales and customer payments (1) (126,981 ) (33,554 ) Loss on sale — (88 ) Decrease/(increase) in valuation allowance (110 ) — Transfers (2) 22 (4,956 ) Write offs and other (3) (2,577 ) (2,393 ) Ending balance $ 14,765 $ 104,850 (1) Customer payments include accrued interest and fees, recoveries of previously charged-off loan receivables held for sale, as well as proceeds from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. We retain servicing arrangements on sold loan receivables with the same terms and conditions as loans that are originated by our Bank Partners. Income from loan receivables held for sale activities is recorded within interest income and other gains/(losses) in the Unaudited Consolidated Statements of Operations. We sold loan receivables held for sale to certain Bank Partners on the following dates during the nine months ended September 30, 2018 and 2017 : 2018 Amount 2017 Amount May 21 $ 9,552 June 29 $ 17,900 June 27 50,614 September 27 48,176 Total $ 108,342 Total $ 17,900 (2) We temporarily hold certain loan receivables, which are originated by a Bank Partner, while non-originating Bank Partner eligibility is being determined. Once we determine that a loan receivable meets the investment requirements of an eligible Bank Partner, we transfer the loan to the Bank Partner at cost plus any accrued interest. The reported amount also includes loans that have been placed on non-accrual and non-payment status while we investigate consumer loan balance inquiries. (3) We received recovery payments of $9 and $29 during the three months ended September 30, 2018 and 2017 , respectively, and $42 and $218 during the nine months ended September 30, 2018 and 2017 , respectively, which are included within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Separately, during the three months ended September 30, 2018 and 2017 , write offs and other were reduced by $113 and $86 , respectively, related to cash proceeds received from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. During the nine months ended September 30, 2018 and 2017 , write offs and other were reduced by $284 and $86 , respectively, related to such cash proceeds. The cash proceeds received were recorded within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Recoveries of principal and finance charges and fees on previously written off loan receivables held for sale are recognized on a collected basis as other gains and interest income, respectively. The following table presents activities associated with our loan receivable sales and servicing activities during the periods indicated. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Gain/(loss) on sold loan receivables held for sale $ — $ — $ — $ (88 ) Cash Flows Sales of loans $ 48,176 $ — $ 108,342 $ 17,900 Servicing fees 546 550 1,645 2,261 The following table presents information about the principal balances of sold loan receivables that are not recorded in our Unaudited Consolidated Balance Sheets, but with which we have a continuing involvement through our servicing arrangements with our Bank Partners. The sold loan receivables are pooled with other loans originated by the Bank Partners for purposes of determining escrow balances and incentive payments. The escrow balances represent our only direct exposure to potential losses associated with these sold loan receivables. September 30, 2018 December 31, 2017 Total principal balance $ 350,296 $ 305,748 Delinquent loans (unpaid principal balance) 24,841 20,409 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net charge-offs (unpaid principal balance) $ 2,017 $ 2,265 $ 6,729 $ 5,270 Accounts Receivable Accounts receivable consisted of the following as of the dates indicated. Accounts Receivable, Gross Allowance for Losses Accounts Receivable, Net September 30, 2018 Transaction related $ 17,605 $ (369 ) $ 17,236 Servicing related 1,387 — 1,387 Total $ 18,992 $ (369 ) $ 18,623 December 31, 2017 Transaction related $ 15,997 $ (276 ) $ 15,721 Servicing related 2,637 — 2,637 Total $ 18,634 $ (276 ) $ 18,358

Accounts Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Accounts Receivable	Loan Receivables Held for Sale The following table summarizes the activity in the balance of loan receivables held for sale at lower of cost or fair value during the periods indicated. Nine Months Ended 2018 2017 Beginning balance $ 73,606 $ 41,268 Additions 70,805 104,573 Proceeds from sales and customer payments (1) (126,981 ) (33,554 ) Loss on sale — (88 ) Decrease/(increase) in valuation allowance (110 ) — Transfers (2) 22 (4,956 ) Write offs and other (3) (2,577 ) (2,393 ) Ending balance $ 14,765 $ 104,850 (1) Customer payments include accrued interest and fees, recoveries of previously charged-off loan receivables held for sale, as well as proceeds from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. We retain servicing arrangements on sold loan receivables with the same terms and conditions as loans that are originated by our Bank Partners. Income from loan receivables held for sale activities is recorded within interest income and other gains/(losses) in the Unaudited Consolidated Statements of Operations. We sold loan receivables held for sale to certain Bank Partners on the following dates during the nine months ended September 30, 2018 and 2017 : 2018 Amount 2017 Amount May 21 $ 9,552 June 29 $ 17,900 June 27 50,614 September 27 48,176 Total $ 108,342 Total $ 17,900 (2) We temporarily hold certain loan receivables, which are originated by a Bank Partner, while non-originating Bank Partner eligibility is being determined. Once we determine that a loan receivable meets the investment requirements of an eligible Bank Partner, we transfer the loan to the Bank Partner at cost plus any accrued interest. The reported amount also includes loans that have been placed on non-accrual and non-payment status while we investigate consumer loan balance inquiries. (3) We received recovery payments of $9 and $29 during the three months ended September 30, 2018 and 2017 , respectively, and $42 and $218 during the nine months ended September 30, 2018 and 2017 , respectively, which are included within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Separately, during the three months ended September 30, 2018 and 2017 , write offs and other were reduced by $113 and $86 , respectively, related to cash proceeds received from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. During the nine months ended September 30, 2018 and 2017 , write offs and other were reduced by $284 and $86 , respectively, related to such cash proceeds. The cash proceeds received were recorded within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Recoveries of principal and finance charges and fees on previously written off loan receivables held for sale are recognized on a collected basis as other gains and interest income, respectively. The following table presents activities associated with our loan receivable sales and servicing activities during the periods indicated. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Gain/(loss) on sold loan receivables held for sale $ — $ — $ — $ (88 ) Cash Flows Sales of loans $ 48,176 $ — $ 108,342 $ 17,900 Servicing fees 546 550 1,645 2,261 The following table presents information about the principal balances of sold loan receivables that are not recorded in our Unaudited Consolidated Balance Sheets, but with which we have a continuing involvement through our servicing arrangements with our Bank Partners. The sold loan receivables are pooled with other loans originated by the Bank Partners for purposes of determining escrow balances and incentive payments. The escrow balances represent our only direct exposure to potential losses associated with these sold loan receivables. September 30, 2018 December 31, 2017 Total principal balance $ 350,296 $ 305,748 Delinquent loans (unpaid principal balance) 24,841 20,409 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net charge-offs (unpaid principal balance) $ 2,017 $ 2,265 $ 6,729 $ 5,270 Accounts Receivable Accounts receivable consisted of the following as of the dates indicated. Accounts Receivable, Gross Allowance for Losses Accounts Receivable, Net September 30, 2018 Transaction related $ 17,605 $ (369 ) $ 17,236 Servicing related 1,387 — 1,387 Total $ 18,992 $ (369 ) $ 18,623 December 31, 2017 Transaction related $ 15,997 $ (276 ) $ 15,721 Servicing related 2,637 — 2,637 Total $ 18,634 $ (276 ) $ 18,358

Property, Equipment and Softwar

Property, Equipment and Software	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Property, Equipment and Software	Property, Equipment and Software Property, equipment and software were as follows as of the dates indicated. September 30, 2018 December 31, 2017 Furniture $ 2,813 $ 2,704 Leasehold improvements 4,114 3,659 Computer hardware 3,012 2,987 Software 7,244 4,836 Total property, equipment and software, at cost 17,183 14,186 Less: accumulated depreciation (5,162 ) (4,060 ) Less: accumulated amortization (2,253 ) (2,278 ) Total property, equipment and software, net $ 9,768 $ 7,848

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Borrowings	Borrowings Credit Agreement In August 2017, we entered into a $450.0 million credit agreement (“Credit Agreement”), which provided for a $350.0 million term loan (“original term loan”) maturing on August 25, 2024 and a $100.0 million revolving loan facility maturing on August 25, 2022. Original term loan. The original term loan incurred interest, due quarterly in arrears, at an adjusted LIBOR rate, which represented the one-month LIBOR rate multiplied by the statutory reserve rate, as defined in the Credit Agreement, plus a margin of 4.00% per annum. An original issuance discount of $3,500 and debt issuance costs of $7,949 were recorded as a direct deduction from the face amount of the original term loan and were being amortized into interest expense over the term of the loan using the effective interest method. The net proceeds from the term loan of $338.6 million , along with $7.9 million of cash, were set aside for a subsequent $346.5 million payment (which is occurring in stages) to certain equity holders and a related party. With the exception of the payments to the related party, which are related party expenses, the payments were accounted for as distributions. As of September 30, 2018 , $340.7 million of the reserved payment was paid in cash. The remaining $5.8 million of the reserved payment was included within other liabilities and related party liabilities in the Unaudited Consolidated Balance Sheets as of September 30, 2018 . The distribution to GS Holdings unit holders and GS Holdings holders of profits interests was made on a basis generally proportionate to their equity interests in GS Holdings. GS Holdings' members approved the Credit Agreement and the distribution of the proceeds of the original term loan to the GS Holdings unit holders, holders of profits interests and a related party. The purpose of the distribution was to provide a cash return on investment to the GS Holdings members and holders of profits interests. Revolving loan facility. Under the revolving loan facility, revolving loans incur interest at our election at either (i) a base rate, which represents, for any day, a rate per annum equal to the greater of (a) the prime rate on such day, (b) the federal funds rate on such day plus 0.50% , and (c) the adjusted LIBOR for a one-month interest period on such day plus 1.00% , plus a margin of 3.00% per annum or (ii) an adjusted LIBOR rate, as discussed below, plus a margin of 4.00% per annum. If our first lien net leverage ratio, as discussed further below, is equal to or below 1.50 to 1.00 , these interest margins are reduced to 2.75% and 3.75% for base rate loans and Eurodollar loans, respectively. As of September 30, 2018 and December 31, 2017 , we had no borrowings under the revolving loan facility. We are required to pay a quarterly commitment fee at a per annum rate of 0.50% on the daily unused amount of the revolving loan facility, inclusive of the aggregate amount available to be drawn under all outstanding letters of credit, of which there were $10.0 million as of September 30, 2018 and $0.0 million as of December 31, 2017 as discussed further below. This rate is reduced to 0.375% for any quarterly period in which our first lien net leverage ratio is equal to or below 1.50 to 1.00. For the three months ended September 30, 2018 and 2017 , we recognized $96 and $49 , respectively, of commitment fees within interest expense in the Unaudited Consolidated Statements of Operations. For the nine months ended September 30, 2018 and 2017 , we recognized $317 and $49 , respectively, of commitment fees within interest expense in the Unaudited Consolidated Statements of Operations. Amended Credit Agreement In March 2018, we amended certain terms of our Credit Agreement ("Amended Credit Agreement"). The term loan and revolving loan facility under the Amended Credit Agreement are collectively referred to as the "Credit Facility." Term loan. The Amended Credit Agreement replaced the original term loan with a $400.0 million term loan (“modified term loan”) and extended the maturity date to March 29, 2025. Further, the interest margin on the modified term loan was reduced to 3.25% per annum. We contemporaneously settled the outstanding principal balance on the original term loan of $349.1 million with the issuance of the $400.0 million modified term loan. An original issuance discount of $1.0 million was reported in the Unaudited Consolidated Balance Sheets as a direct deduction from the face amount of the modified term loan. Therefore, the gross proceeds of the modified term loan were $399.0 million . The proceeds from the modified term loan were primarily used to repay the outstanding principal balance on the original term loan and to pay $1.1 million of third party costs, including legal and debt arrangement costs, which were immediately expensed and recorded within general and administrative expense in the Unaudited Consolidated Statements of Operations on the modification date. The remaining $48.8 million of proceeds were used to provide for distributions to certain equity holders and a related party prior to the IPO. As of September 30, 2018 , $46.9 million of the distribution was paid in cash. The remaining $1.8 million and $0.1 million of the reserved payment were included within other liabilities and related party liabilities, respectively, in the Unaudited Consolidated Balance Sheets as of September 30, 2018 . Key details of the term loans are as follows: September 30, 2018 (1) December 31, 2017 (1) Term loan, face value (2) $ 398,000 $ 349,125 Unamortized debt discount (3) (3,882 ) (3,321 ) Unamortized debt issuance costs (3) (6,717 ) (7,541 ) Term loan $ 387,401 $ 338,263 (1) Amounts reported reflect details of the original term loan as of December 31, 2017 , and details of the modified term loan as of September 30, 2018 . (2) The principal balance of the original term loan was scheduled to be repaid on a quarterly basis at an amortization rate of 0.25% per quarter. We made the first principal payment in December 2017. The principal balance of the modified term loan is scheduled to be repaid on a quarterly basis at an amortization rate of 0.25% per quarter, with the balance due at maturity. We made the first principal payment on the modified term loan in June 2018. For each of the next five years, principal repayments on the modified term loan are expected to be $4,000 . (3) For the three months ended September 30, 2018 and 2017 , $155 and $52 of debt discount and $267 and $119 of debt issuance costs, respectively, were amortized into interest expense in the Unaudited Consolidated Statements of Operations. For the nine months ended September 30, 2018 and 2017 , $438 and $52 of debt discount and $824 and $119 of debt issuance costs, respectively, were amortized into interest expense in the Unaudited Consolidated Statements of Operations. Revolving loan facility. Under the Amended Credit Agreement, the maturity date of the $100.0 million revolving loan facility was extended to March 29, 2023. Further, the interest margin applied to revolving loans that incur interest at a base rate was modified to 2.00% per annum and the margin applied to revolving loans that incur interest at an adjusted LIBOR rate was modified to 3.00% per annum. However, if our first lien net leverage ratio is equal to or above 1.50 to 1.00, these interest margins are raised to 2.25% and 3.25% , respectively. As of September 30, 2018 , we had no borrowings under the revolving loan facility. Lastly, the Amended Credit Agreement provided for a $10.0 million letter of credit, which, to the extent drawn upon, would reduce the amount of availability under the revolving loan facility by the same amount. We did not draw on our available letter of credit as of September 30, 2018 . The Credit Agreement commitment fee rates on the revolving loan facility (inclusive of the letter of credit), as disclosed above, were not changed. Covenants The Amended Credit Agreement contains certain financial and non-financial covenants with which we must comply. The financial covenant requires a first lien net leverage ratio equal to or below 3.50 to 1.00 for any measurement date at which the principal amounts of outstanding revolving loans and letters of credit exceed 25% of the aggregate principal amount of the revolving loan facility. The first lien net leverage ratio is calculated as the ratio of (i) the aggregate principal amount of indebtedness, minus the aggregate amount of consolidated cash (exclusive of restricted cash), as of the measurement date to (ii) consolidated EBITDA, as defined in the Amended Credit Agreement, for the four prior quarters. The non-financial covenants include, among other things, restrictions on indebtedness, liens, fundamental changes to the business (such as acquisitions, mergers, liquidations or changes in the nature of the business, asset dispositions, restricted payments, transactions with affiliates and other customary matters). The Amended Credit Agreement also includes various negative covenants, including one that restricts GS Holdings from making non-tax distributions unless certain financial tests are met. In general, GS Holdings is restricted from making distributions unless (a) after giving effect to the distribution it would have, as of a measurement date, a total net leverage ratio of no more than 3.00 to 1.00, and (b) the source of such distributions is retained excess cash flow, certain equity issuance proceeds and certain other sources. We were in compliance with all covenants, both financial and non-financial, as of September 30, 2018 and December 31, 2017 . The Amended Credit Agreement defines events of default, the breach of which could require early payment of all borrowings under, and termination of, the Amended Credit Agreement or similar actions. Any borrowings under the Amended Credit Agreement are unconditionally guaranteed by our subsidiaries. Further, the lenders have a security interest in substantially all of the assets of GS Holdings and the other guarantors thereunder. Initial Credit Facility On February 10, 2017, GSLLC entered into an agreement (“Initial Credit Facility Agreement”) for a two -year, $50.0 million bank revolving credit facility (“Initial Credit Facility”), which was expandable, upon our request and successful syndication, to $100.0 million . The Initial Credit Facility Agreement also allowed us to request the issuance of letters of credit denominated in United States dollars as the applicant thereof for the support of our or our subsidiaries’ obligations. In conjunction with the Credit Agreement, on August 25, 2017, we terminated the Initial Credit Facility, at which time we had no borrowings under the facility, nor requests for letters of credit. During the three and nine months ended September 30, 2017 , we recorded commitment fees on the daily unused amount of each lender’s commitment under the Initial Credit Facility of $61 and $159 , respectively, which were recorded within interest expense in the Unaudited Consolidated Statements of Operations. Further, we recorded up-front and other fees associated with the Initial Credit Facility within other assets in the Unaudited Consolidated Balance Sheet, which were amortized on a straight-line basis over the remaining term of the Initial Credit Facility into interest expense in the Unaudited Consolidated Statements of Operations. For the three and nine months ended September 30, 2017 , we recorded $24 and $99 , respectively, of amortization of such fees within interest expense in the Unaudited Consolidated Statements of Operations. We incurred debt extinguishment costs of $254 during the three and nine months ended September 30, 2017 upon termination of the Initial Credit Facility, which were recorded within other gains/(losses) in the Unaudited Consolidated Statements of Operations.

Other Liabilities

Other Liabilities	9 Months Ended
	Sep. 30, 2018
Other Liabilities Disclosure [Abstract]
Other Liabilities	Other Liabilities The following table details the components of other liabilities in the Unaudited Consolidated Balance Sheets as of the dates indicated. September 30, 2018 December 31, 2017 Deferred lease liabilities $ 2,618 $ 2,819 Transaction processing liabilities 18,741 16,435 Servicing liabilities (1) 2,692 2,071 Distributions payable (2) 10,565 13,189 Accruals and other liabilities 5,033 4,327 Total other liabilities $ 39,649 $ 38,841 (1) Refer to Note 3 for additional information on servicing liabilities. (2) Related party distributions payable are not included in this balance, but rather are included within related party liabilities.

Noncontrolling Interests

Noncontrolling Interests	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Noncontrolling Interests GreenSky, Inc. is the sole managing member of GS Holdings and consolidates the financial results of GS Holdings. Therefore, the Company reports a noncontrolling interest based on the common units of GS Holdings held by the Continuing LLC Members. Changes in GreenSky, Inc.’s ownership interest in GS Holdings, while GreenSky, Inc. retains its controlling interest in GS Holdings, are accounted for as equity transactions. As such, future redemptions or direct exchanges of common units of GS Holdings by the Continuing LLC Members will result in a change in ownership and reduce or increase the amount recorded as noncontrolling interest and increase or decrease additional paid-in capital when GS Holdings has positive or negative net assets, respectively. As of September 30, 2018 , GreenSky, Inc. had 57,797,385 shares of Class A common stock outstanding, which resulted in an equivalent amount of ownership of GS Holdings common units. When adjusted for unvested units, GreenSky, Inc. had a 31.3% economic ownership interest in GS Holdings.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation In anticipation of our IPO, the Company adopted the 2018 Omnibus Incentive Compensation Plan (the "2018 Plan") in April 2018. The Company reserved a total of 24,000,000 shares of Class A common stock for issuance pursuant to the 2018 Plan. The Company currently has three types of share-based compensation awards outstanding; namely, Class A common stock options, unvested Holdco Units and unvested Class A common stock awards. Class A Common Stock Options Class A common stock option ("Options") activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Number of Options Weighted Average Exercise Price Number of Options Outstanding at beginning of period 9,821,884 $ 2.65 10,006,890 Granted prior to Reorganization Transactions and IPO (1) 340,000 14.95 450,000 Exercised prior to Reorganization Transactions and IPO (2)(3) (270,000 ) 3.19 (202,000 ) Forfeited prior to Reorganization Transactions and IPO (260,000 ) 6.41 (400,500 ) Effect of Reorganization Transactions and IPO (186,772 ) 7.56 N/A Granted after the Reorganization Transactions and IPO (1) 1,014,029 21.72 N/A Exercised after Reorganization Transactions and IPO (3) (42,000 ) 1.39 N/A Forfeited after Reorganization Transactions and IPO (202,000 ) 19.34 N/A Outstanding at end of period (4) 10,215,141 $ 4.43 9,854,390 Exercisable at end of period (4) 7,237,582 $ 1.54 6,718,500 (1) Weighted average grant date fair value of Options granted during the nine months ended September 30, 2018 and 2017 was $6.29 and $3.42 , respectively. (2) The total intrinsic value of Options exercised, which is defined as the amount by which the market value of the stock on the date of exercise exceeds the exercise price, during the nine months ended September 30, 2018 and 2017 was $1,475 and $396 , respectively. (3) Employees paid $339 during the nine months ended September 30, 2018 to the Company to exercise Options, which resulted in the issuance of 30,516 Holdco Units prior to the Reorganization Transactions and IPO. Additionally, during the nine months ended September 30, 2018 , 252,000 Options were exercised by means of a cashless net exercise procedure, which resulted in the issuance of 38,637 Holdco Units prior to the Reorganization Transactions and IPO and the issuance of 9,964 shares of Class A common stock subsequent to the Reorganization Transactions and IPO. (4) The aggregate intrinsic value and weighted average remaining contractual terms of Options outstanding and Options exercisable were as follows as of September 30, 2018 : September 30, 2018 Aggregate intrinsic value (in millions) Unit Options outstanding $ 56.1 Unit Options exercisable $ 45.7 Weighted average remaining term (in years) Unit Options outstanding 5.42 Unit Options exercisable 4.41 Profits Interests Profits interests activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Number of Weighted Number of Outstanding at beginning of period 14,061,530 $ 8.23 12,616,890 Granted prior to Reorganization Transactions and IPO (1) 2,920,000 14.31 420,000 Forfeited prior to Reorganization Transactions and IPO (800,000 ) 9.32 (880,000 ) Redeemed prior to Reorganization Transactions and IPO — N/A — Effect of Reorganization Transactions and IPO (16,181,530 ) 9.27 N/A Outstanding at end of period (2) — N/A 12,156,890 (1) Weighted average grant date fair value of profits interests granted during the nine months ended September 30, 2018 and 2017 was $4.47 and $2.71 , respectively. (2) The total fair value based on grant date fair value of profits interests that vested was $371 and $1,204 during the nine months ended September 30, 2018 and 2017 , respectively. Unvested Holdco Units As part of the Reorganization Transactions and the IPO, 15,241,530 profits interests in GS Holdings were converted into 2,941,139 and 3,172,843 vested and unvested Holdco Units, respectively, based on the prevailing profits interests thresholds and the IPO price of $23.00 per share. The converted Holdco Units remain subject to the same service vesting requirements of the original profits interests. Unvested Holdco Units activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Holdco Units Weighted Average Grant Date Fair Value Holdco Units Unvested at beginning of period — N/A N/A Effect of Reorganization Transactions and IPO 3,172,843 $ 23.00 N/A Granted — N/A N/A Forfeited (156,739 ) 23.00 N/A Vested (1) (118,082 ) 23.00 N/A Unvested at end of period 2,898,022 $ 23.00 N/A (1) The total fair value, based on grant date fair value, of previously unvested Holdco Units that vested during the nine months ended September 30, 2018 was $2,716 . Unvested Class A Common Stock Awards As part of the Reorganization Transactions and the IPO, 940,000 profits interests in GS Holdings were converted into 127,327 and 255,904 vested and unvested Class A common stock awards, respectively, based on the prevailing profits interests thresholds and the IPO price of $23.00 per share. The converted unvested Class A common stock awards are subject to the same service vesting requirements of the original profits interests. Subsequent to the Reorganization Transactions and the IPO, we granted unvested Class A common stock awards to certain employees that vest ratably over a four-year period based on continued employment at the Company. Unvested Class A common stock awards are valued based on the closing stock price of the Company's Class A common stock on the date of grant, and the total value of the awards is expensed ratably over the requisite service period. Unvested Class A common stock award activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Class A common stock Weighted Average Grant Date Fair Value Class A common stock Unvested at beginning of period — N/A N/A Effect of Reorganization Transactions and IPO 255,904 $ 23.00 N/A Granted 137,170 19.71 N/A Forfeited — N/A N/A Vested (1) (15,049 ) 23.00 N/A Unvested at end of period 378,025 $ 21.81 N/A (1) The total fair value, based on grant date fair value, of previously unvested Class A common stock awards that vested during the nine months ended September 30, 2018 was $346 . Historical information prior to the Reorganization Transactions has been restated above to account for the 10 to 1 stock split that occurred immediately prior to the IPO in connection with the Reorganization Transactions. We recorded share-based compensation expense of $4,304 and $3,032 for the nine months ended September 30, 2018 and 2017 , respectively, which is included within compensation and benefits expense in the Unaudited Consolidated Statements of Operations. At September 30, 2018 , unrecognized compensation costs related to nonvested Options totaled $9.7 million, which will be recognized over a weighted average remaining requisite service period of 4.1 years. At September 30, 2018 , unrecognized compensation costs related to unvested Holdco Unit awards totaled $14.4 million, which will be recognized over a weighted average remaining requisite service period of 3.8 years. At September 30, 2018 , unrecognized compensation costs related to unvested Class A common stock totaled $4.1 million, which will be recognized over a weighted average remaining requisite service period of 4.0 years.

Taxation

Taxation	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Taxation	Taxation GreenSky, Inc. is taxed as a corporation and pays corporate federal, state and local taxes on income allocated to it from GS Holdings based upon GreenSky, Inc.’s economic interest held in GS Holdings. GS Holdings is treated as a pass-through partnership for income tax reporting purposes. GS Holdings’ members, including GreenSky, Inc., are liable for federal, state and local income taxes based on their share of GS Holdings’ pass-through taxable income. The Company’s effective tax rate for the three and nine months ended September 30, 2018 was 6.9% and 4.5% , respectively, and the Company recorded $3,375 and $4,969 of income tax expense for the three and nine months ended September 30, 2018 , respectively. The Company’s effective tax rates for the three and nine months ended September 30, 2018 were less than our combined federal and state statutory tax rate of 23.5% , primarily because the Company is not liable for income taxes on the portion of GS Holdings’ earnings that are attributable to noncontrolling interests. Further, prior to the Reorganization Transactions, GS Holdings' earnings were completely exempt from federal corporate income taxation. The results from the three and nine months ended September 30, 2017 do not reflect income tax expense because, prior to the Reorganization Transactions, the consolidated GS Holdings pass-through entity was not subject to corporate tax. The Company regularly monitors its uncertain tax benefits and, as of September 30, 2018 , there were no material uncertain tax benefits that if realized would affect the estimated annual effective tax rate, nor were there positions for which it is reasonably possible that the total amount of uncertain tax benefits would significantly increase or decrease within the next 12 months. As a result of the IPO and Reorganization Transactions, the Company recognized a net deferred tax asset in the amount of $ 245,836 primarily associated with the basis difference in our investment in GS Holdings. During the nine months ended September 30, 2018 , we also recognized $ 57,116 of deferred tax assets related to additional tax basis increases generated from expected future payments under a TRA with certain of the then-existing members of GS Holdings and related deductions for imputed interest on such payments. See "Tax receivable agreement liability" below for more information. We evaluate the realizability of our deferred tax assets on a quarterly basis and establish valuation allowances when it is more likely than not that all or a portion of a deferred tax asset may not be realized. As of September 30, 2018 , we concluded, based on the weight of all available positive and negative evidence, that all of our deferred tax assets are more likely than not to be realized. As such, no additional valuation allowance was recognized. The Company did not recognize any change to the valuation allowance through the provision for income tax for the three or nine months ended September 30, 2017 because, prior to the Reorganization Transactions, GreenSky, Inc., did not have any operations or investments and, therefore, did not have any deferred tax assets. Tax receivable agreement liability Pursuant to our election under Section 754 of the Internal Revenue Code (the "Code"), we expect to obtain an increase in our share of the tax basis in the net assets of GS Holdings when Holdco Units are redeemed or exchanged by the Continuing LLC Members of GS Holdings. We intend to treat any redemptions and exchanges of Holdco Units as direct purchases of Holdco Units for U.S. federal income tax purposes. These increases in tax basis may reduce the amounts that we would otherwise pay in the future to various tax authorities. They may also decrease gains (or increase losses) on future dispositions of certain capital assets to the extent tax basis is allocated to those capital assets. On May 23, 2018, we entered into a TRA that provides for the payment by us of 85% of the amount of any tax benefits that we actually realize, or in some cases are deemed to realize, as a result of (i) increases in our share of the tax basis in the net assets of GS Holdings resulting from any redemptions or exchanges of Holdco Units and from our acquisition of the equity of certain of the Former Corporate Investors, (ii) tax basis increases attributable to payments made under the TRA, and (iii) deductions attributable to imputed interest pursuant to the TRA (the "TRA Payments"). We expect to benefit from the remaining 15% of any tax benefits that we may actually realize. The TRA Payments are not conditioned upon any continued ownership interest in GS Holdings or us. The rights of each member of GS Holdings that is a party to the TRA are assignable to transferees of their respective Holdco Units. The timing and amount of aggregate payments due under the TRA may vary based on a number of factors, including the timing and amount of taxable income generated by the Company each year, as well as the tax rate then applicable. As of September 30, 2018 , the Company had a liability of $255.8 million related to its projected obligations under the TRA, which is captioned as tax receivable agreement liability in our Unaudited Consolidated Balance Sheets.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees Commitments We primarily lease our premises under multi-year, non-cancelable operating leases with terms expiring through 2024, exclusive of renewal option periods. Our lease agreement expiring in 2024 also contains a renewal option, at our election, to extend the lease for five consecutive three -year periods. Base rent is subject to rent escalations on each annual anniversary from the lease commencement dates. Rental payments, as well as any step rent provisions specified in the lease agreements, are aggregated and charged evenly to expense over the lease term. Certain of these operating leases contain rent holidays and tenant allowances that may be applied toward leasehold improvements or other lease concessions. Capital improvement funding and other lease concessions provided by the landlord are recorded as deferred liabilities and are amortized evenly over the lease term as a reduction of rent expense. In most circumstances, we expect that in the normal course of business, leases will be renewed or replaced by other leases. Rent expense is recognized on a straight-line basis over the life of the lease and is included within property, office and technology and related party expenses in the Unaudited Consolidated Statements of Operations. Refer to Note 13 for additional information regarding office space leased from a related party. Rent expense was $810 and $759 for the three months ended September 30, 2018 and 2017 , respectively. Rent expense was $2,366 and $2,234 for the nine months ended September 30, 2018 and 2017 , respectively. As of September 30, 2018 , future minimum lease payments under our leases for the periods presented are as follows: September 30, 2018 Remainder of 2018 $ 907 2019 3,725 2020 3,815 2021 3,878 2022 2,827 2023 and thereafter 1,647 Total minimum lease payments $ 16,799 Our transaction processor imposes certain financial covenants upon our wholly owned subsidiary, GSLLC. The financial covenants with our transaction processor apply only to GSLLC and include the following: • Tangible net worth, as defined in the agreement, of no less than $7.5 million ; • Minimum aggregate net income of $5.0 million for the trailing four fiscal quarters; and • Ratio of total liabilities to total equity not to exceed 3.00 :1.00. As of September 30, 2018 , GSLLC was in compliance with all financial covenants. As of September 30, 2018 , our outstanding open and unused line of credit on approved loan receivables held for sale was $3.8 million . We did not record a provision for these unfunded commitments, but believe we have adequate cash on hand to fund these commitments. For certain Bank Partners, we maintain a restricted cash balance based on a contractual percentage of the total interest billed on outstanding deferred interest loans that are within the promotional period less previous FCR on such outstanding loans. As of September 30, 2018 , restricted cash in the Unaudited Consolidated Balance Sheets includes $44.7 million associated with these arrangements. Contingencies In limited instances, the Company may be subject to operating losses if we make certain errors in managing credit programs and we determine that a customer is not liable for a loan originated by a Bank Partner. We evaluated this contingency in accordance with ASC 450, Contingencies , and determined that it is reasonably possible that losses could result from errors in underwriting. However, in management’s opinion, it is not possible to estimate the likelihood or range of reasonably possible future losses related to errors in underwriting based on currently available information. Therefore, we have not established a liability for this loss contingency. Further, from time to time, we place Bank Partner loans on non-accrual and non-payment status (“Pended Status”) while we investigate consumer loan balance inquiries, which may arise from disputed charges related to work performed by third-party merchants. As of September 30, 2018 , Bank Partner loan balances in Pended Status were $15.7 million . While it is management’s expectation that most of these loan balance inquiries will be resolved without incident, in certain instances we may determine that it is appropriate for the Company to permanently reverse the loan balance and assume the economic responsibility for the loan balance itself. We record a liability for these instances. As of September 30, 2018 , our liability for potential Pended Status future losses was $2.7 million . From time to time, we may become a party to civil claims and lawsuits. As of September 30, 2018 , we were not a party as a defendant to any litigation that we believed was material to our operations or results. Financial guarantees Under the terms of the contracts with our Bank Partners, a contractual percentage of the Bank Partners’ monthly originations and month-end outstanding portfolio balance is held and maintained in restricted, interest-bearing escrow accounts to serve as limited protection to the Bank Partners in the event of excess Bank Partner portfolio credit losses. The Company’s maximum exposure to Bank Partner portfolio credit losses is limited to the contractual restricted cash balance, which was $91.2 million as of September 30, 2018 . The recorded fair value of the financial guarantee related to these contracts was $0.5 million as of September 30, 2018 , which was recorded within other liabilities in the Unaudited Consolidated Balance Sheets. Recorded financial guarantees are typically settled within one year of the initial measurement of the liability. In determining the measured liabilities, we consider a variety of factors, including historical experience and management’s expectations of current customer delinquencies converting into Bank Partner portfolio losses. We do not expect to directly recover any losses associated with this financial guarantee.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions We lease office space from a related party under common management control for which rent expenses are recognized within related party expenses in the Unaudited Consolidated Statements of Operations. Total rent expenses related to this office space were $439 and $373 for the three months ended September 30, 2018 and 2017 , respectively, and $1,252 and $1,118 for the nine months ended September 30, 2018 and 2017 , respectively. In April 2018, we entered into an agreement with an affiliate of a member of the board of directors whereby we receive certain executive search and recruiting services in exchange for a fee. We incurred expenses related to this arrangement of $375 and $375 during the three and nine months ended September 30, 2018 , respectively, which are presented within related party expenses in the Unaudited Consolidated Statements of Operations. We have a payable related to this arrangement of $61 as of September 30, 2018 , which is presented within related party payables in the Unaudited Consolidated Balance Sheets. We entered into non-interest bearing loan agreements with certain non-executive employees for which the remaining outstanding balances will be forgiven ratably over designated periods based on continual employment with the Company. As of September 30, 2018 and December 31, 2017 , the remaining outstanding balances on these loan agreements were $122 and $210 , respectively, which are presented within related party receivables in the Unaudited Consolidated Balance Sheets. There were no equity-based payments to non-employees that resulted in related party expenses for the three and nine months ended September 30, 2018 . Equity-based payments to non-employees resulted in related party expenses of $95 and $285 for the three and nine months ended September 30, 2017 , respectively. In May 2018, we declared a special operating distribution of $26.2 million. As of September 30, 2018 , $25.1 million of the declared distribution was paid in cash, including $1.0 million to an affiliate of a related party. The remaining portion of the declared distribution will be paid in stages upon vesting events and is recorded within related party liabilities ( $0.2 million) and other liabilities ( $0.9 million) in the Unaudited Consolidated Balance Sheets as of September 30, 2018 . In August 2017, we incurred fees of $2.6 million due to an affiliate of one of the members of the board of managers in connection with finalizing our August 2017 term loan transaction. These costs were not directly attributable to the original term loan and were, therefore, expensed as incurred rather than deferred against the term loan balance. The unpaid portion of these fees of $0.5 million is recorded within related party liabilities in the Unaudited Consolidated Balance Sheets as of September 30, 2018 . In November 2016, we executed a $20.0 million Bank Partner agreement (“2016 Agreement”) with affiliates of two members of our board of directors. The agreement was structured similarly to the origination and servicing arrangements with the other Bank Partners, wherein the Company was required to hold restricted cash based on monthly originations and the month-end outstanding portfolio balance. In June 2018, the outstanding loans owned by this related party were sold to another Bank Partner, which is not a related party, and continue to be serviced by us. In connection with that loan sale, the related party financing partner ended its servicing agreement with us. As of September 30, 2018 , we no longer have any related party financing partner agreements. We were entitled to collect fixed servicing fees in conjunction with the 2016 Agreement. As of September 30, 2018 and December 31, 2017 , our related party financing partners had committed balances in the aggregate of $0.0 million and $11.7 million, respectively. Unaudited Consolidated Balance Sheets effects associated with our related party financing partners were as follows at the dates indicated: September 30, 2018 December 31, 2017 Related party receivables (1) $ — $ 8 Related party liabilities (2) — 445 Restricted cash — 437 (1) Receivables related to servicing and other. (2) Related party liabilities primarily consisted of related party servicing payables. Unaudited Consolidated Statements of Operations effects associated with our related party financing partners were as follows during the periods indicated and include the income related impact of our two previous related party financing arrangements that were terminated in June 2018 and June 2017, respectively. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Servicing and other $ — $ 32 $ 54 $ 248 Related party expenses (1) — — — 69 (1) Expenses incurred related to related party financing partner credit losses.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We conduct our operations through a single operating segment and, therefore, one reportable segment. Operating segments are revenue-generating components of a company for which separate financial information is internally produced for regular use by the Chief Operating Decision Maker (“CODM”) to allocate resources and assess the performance of the business. Our CODM uses a variety of measures to assess the performance of the business; however, detailed profitability information of the nature that could be used to allocate resources and assess the performance of the business are managed and reviewed for the Company as a whole. There are no significant concentrations by state or geographical location, nor are there any significant individual customer concentrations by balance.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities Upon completion of our IPO, GreenSky, Inc. became the managing member of GS Holdings with 100% of the management and voting power in GS Holdings. In its capacity as managing member, GreenSky, Inc. has the sole authority to make decisions on behalf of GS Holdings and bind GS Holdings to signed agreements. Further, GS Holdings maintains separate capital accounts for its investors as a mechanism for tracking earnings and subsequent distribution rights. Accordingly, management concluded that GS Holdings is a limited partnership or similar legal entity as contemplated in ASC 810, Consolidation . Further, management concluded that GreenSky, Inc. is GS Holdings' primary beneficiary. As the primary beneficiary, GreenSky, Inc. consolidates the results of GS Holdings for financial reporting purposes under the variable interest consolidation model guidance in ASC 810. GreenSky, Inc.’s relationship with GS Holdings results in no recourse to the general credit of GreenSky, Inc. GS Holdings and its consolidated subsidiaries represent GreenSky, Inc.’s sole investment. GreenSky, Inc. shares in the income and losses of GS Holdings in direct proportion to GreenSky, Inc.’s ownership percentage. Further, GreenSky, Inc. has no contractual requirement to provide financial support to GS Holdings. Below are tabular disclosures that provide insight into how GS Holdings affects GreenSky, Inc.’s financial position, performance and cash flows. Prior to the IPO and Reorganization Transactions, GreenSky, Inc. was not impacted by GS Holdings and, therefore, 2017 periods are not presented below. The following table presents the balances related to GS Holdings that are included in the Unaudited Consolidated Balance Sheets, as well as GreenSky, Inc.'s interest in the variable interest entity ("VIE") at September 30, 2018 . September 30, 2018 Assets Cash $ 285,310 Restricted cash 160,909 Loan receivables held for sale, net 14,765 Accounts receivable, net 18,623 Related party receivables 122 Property, equipment and software, net 9,768 Other assets 4,989 Total assets $ 494,486 Liabilities and Members Equity (Deficit) Liabilities Accounts payable $ 6,134 Accrued compensation and benefits 5,525 Other accrued expenses 1,013 Finance charge reversal liability 117,202 Term loan 387,401 Related party liabilities 937 Other liabilities 39,649 Total liabilities 557,861 Members Equity (Deficit) Equity (deficit) attributable to Continuing LLC Members (41,533 ) Equity (deficit) attributable to GreenSky, Inc. (21,842 ) Total members equity (deficit) (63,375 ) Total liabilities and members equity (deficit) $ 494,486 The following table reflects the impact of consolidation of GS Holdings into the Unaudited Consolidated Statements of Operations for the three and nine months ended September 30, 2018 . Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 Total operating revenue $ 113,912 $ 304,942 Total operating expenses 59,655 180,300 Operating profit 54,257 124,642 Total other income/(expense), net (5,170 ) (14,541 ) Net income $ 49,087 $ 110,101 The following table reflects the cash flow impact of GS Holdings on the Unaudited Consolidated Statement of Cash Flows during the nine months ended September 30, 2018 : Nine Months Ended September 30, 2018 Net cash provided by operating activities $ 203,421 Net cash used in investing activities (4,849 ) Net cash used in financing activities (106,191 ) Net increase in cash and restricted cash 92,381 Cash and restricted cash at beginning of period 353,838 Cash and restricted cash at end of period $ 446,219

Temporary Equity

Temporary Equity	9 Months Ended
	Sep. 30, 2018
Temporary Equity Disclosure [Abstract]
Temporary Equity	Temporary Equity Prior to the IPO and Reorganization Transactions, GreenSky Holdings, LLC had outstanding Class B and Class C Preferred Units, which were accounted for as temporary equity because of redemption preferences. The redemption preferences were waived on both the Class B and Class C Preferred Units in conjunction with the IPO and, therefore, temporary equity had a balance of $0 as of September 30, 2018 . Below are more details on the accounting treatment prior to the IPO and Reorganization Transactions. Class B Preferred Units Prior to the IPO, Class B unit holders collectively were entitled to a liquidation preference prior to any distribution to the holders of any other equity securities, which liquidation preference became null and void upon consummation of the IPO. Accordingly, as of September 30, 2018 , the Class B liquidation preference is of no further effect because of the IPO. As of December 31, 2017 , the redemption amount of the Class B Preferred Units, which was adjusted for non-tax GS Holdings member distributions, was $215.8 million . The liquidation preference was further adjusted for non-tax GS Holdings distributions during 2018 prior to the IPO. Class C Preferred Units Prior to the IPO, Class C-1 and C-2 unit holders collectively were entitled to a liquidation preference prior to any distribution to Class A unit holders, but in the event of an IPO, the Class C units automatically convert into GS Holdings Class A units immediately prior to the IPO. Accordingly, as of September 30, 2018 , Class C-1 and C-2 liquidation preferences are of no further effect because of the IPO. As of December 31, 2017 , the redemption amounts of the Class C-1 and Class C-2 Preferred Units, which were adjusted for non-tax GS Holdings member distributions, were $191.4 million for Class C-1 Preferred Units and $43.0 million for Class C-2 Preferred Units. The liquidation preferences were further adjusted for non-tax GS Holdings distributions during 2018 prior to the IPO.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Management of the Company performed an evaluation of subsequent events through November 9, 2018 , which is the date the financial statements were issued. On October 24, 2018, the Company purchased $20.1 million of loan receivables held for sale from one of the Company's Bank Partners. This loan receivable held for sale purchase also includes a maximum unfunded commitment of $11.2 million , which would be funded by the Company in the event that all borrowers utilize their maximum approved line of credit. There were no additional subsequent events noted in management’s evaluation that would require disclosure.

Organization, Summary of Sign_2

Organization, Summary of Signifant Accounting Policies and New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization GreenSky, Inc. (or the "Company," "we" or "our") was formed as a Delaware corporation on July 12, 2017. The Company was formed for the purpose of completing an IPO of its Class A common stock and certain Reorganization Transactions, as further described below, in order to carry on the business of GreenSky Holdings, LLC (“GS Holdings”) and its consolidated subsidiaries. GS Holdings, a holding company with no operating assets or operations, was organized in August 2017. On August 24, 2017, GS Holdings acquired a controlling interest in GreenSky, LLC ("GSLLC"), a Georgia limited liability company, which is an operating entity. Common membership interests of GS Holdings are referred to as "Holdco Units." Immediately prior to our IPO, (i) the operating agreement of GS Holdings (the "GS Holdings Agreement") was amended and restated to, among other things, modify its capital structure by replacing the different classes of membership interests and profits interests with Holdco Units; (ii) we issued to each of the Continuing LLC Members (as defined below) a number of shares of GreenSky, Inc. Class B common stock equal to the number of Holdco Units held by it (other than the Holdco Units that were exchanged in connection with the IPO), for consideration in the amount of $0.001 per share of Class B common stock; (iii) certain Holdco Units were contributed to GreenSky, Inc. in exchange for shares of our Class A common stock; (iv) equity holders of the Former Corporate Investors (as defined below) contributed their equity in the Former Corporate Investors to GreenSky, Inc. in exchange for shares of our Class A common stock and the right to certain payments under the Tax Receivable Agreement (“TRA”), and Former Corporate Investors merged with and into subsidiaries of GreenSky, Inc.; (v) outstanding options to acquire Class A units of GS Holdings were equitably adjusted so that they are exercisable for shares of Class A common stock; and (vi) outstanding warrants to acquire Class A units of GS Holdings were equitably adjusted pursuant to their terms so that they are exercisable for Holdco Units (and an equal number of shares of Class B common stock). We refer to these transactions collectively as the “Reorganization Transactions.” The Reorganization Transactions are more fully described in our final IPO prospectus dated May 23, 2018 filed with the United States Securities and Exchange Commission on May 25, 2018 (the "Final IPO Prospectus"). Following the Reorganization Transactions, the Original GS Equity Owners (other than the Former Corporate Investors) and certain Original Profits Interests Holders, which we collectively refer to as the "Continuing LLC Members," continue to own Holdco Units. Original GS Equity Owners refers to the owners of units of GS Holdings prior to the Reorganization Transactions. Former Corporate Investors refers to certain of the Original GS Equity Owners that merged with and into one or more subsidiaries of GreenSky, Inc. in connection with the Reorganization Transactions, which was accounted for as a common control transaction and had no material impact on the net assets of the Company. Original Profits Interests Holders refers to the owners of profits interests in GS Holdings prior to the Reorganization Transactions. On May 24, 2018, the Company's Class A common stock commenced trading on the NASDAQ Stock Market in connection with its IPO of 43,700,000 shares of its Class A common stock at a public offering price of $23.00 per share, receiving approximately $954.8 million in net proceeds, after deducting underwriting discounts and commissions (but not including other offering costs), which were used to purchase 2,426,198 shares of Class A common stock and 41,273,802 newly-issued GS Holdings common units at a price per unit equal to the price per share of Class A common stock sold in the IPO, less underwriting discounts and commissions. The newly-issued GS Holdings common units were sold by Continuing LLC Members, which we also refer to as "Exchanging Members." Pursuant to an "Exchange Agreement," the Exchanging Members can exchange their Holdco Units (with automatic cancellation of an equal number of shares of Class B common stock) for shares of our Class A common stock on a one -for-one basis, subject to customary adjustments, or for cash (based on the market price of the shares of Class A common stock), at our option (such determination to be made by the disinterested members of our board of directors). The IPO and Reorganization Transactions resulted in the Company becoming the sole managing member of GS Holdings. As the sole managing member of GS Holdings, we operate and control all of GS Holdings’ operations and, through GS Holdings and its subsidiaries, conduct GS Holdings’ business. As of September 30, 2018 , the Company had an economic interest in GS Holdings of 31.3% , after adjusting for unvested units. The Company consolidates the financial results of GS Holdings and reports a noncontrolling interest in its Unaudited Consolidated Financial Statements representing the GS Holdings interests held by Continuing LLC Members.
Basis of Presentation	Basis of Presentation The balance sheet data as of December 31, 2017 was derived from the audited Consolidated Financial Statements included in our Final IPO Prospectus. The Unaudited Consolidated Financial Statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission for interim financial statements. Accordingly, the Unaudited Consolidated Financial Statements do not include all information and disclosures required by accounting principles generally accepted in the United States that would be required for complete financial statements. In the opinion of management, the Unaudited Consolidated Financial Statements reflect all adjustments, which are of a normal recurring nature, necessary for a fair statement of our statements of operations for the three and nine months ended September 30, 2018 and 2017 , our balance sheets at September 30, 2018 and December 31, 2017 , and our cash flows for the nine months ended September 30, 2018 and 2017 . We condensed or omitted certain notes and other information from the interim financial statements presented in this Quarterly Report on Form 10-Q. Therefore, these interim statements should be read in conjunction with our Final IPO Prospectus. The results for the three and nine months ended September 30, 2018 are not necessarily indicative of results that may be expected for the full year.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with United States generally accepted accounting principles ("GAAP") requires that management make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Such estimates and assumptions include, but are not limited to, those that relate to fair value measurements, share-based compensation and income taxes. In developing estimates and assumptions, management uses all available information; however, actual results could materially differ from those estimates and assumptions.
Recently Adopted Accounting Standards and Accounting Standards Issued but Not Yet Adopted	Recently Adopted Accounting Standards Revenue from contracts with customers In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-09 to clarify the principles for recognizing revenue and to develop a common revenue standard, which is codified in ASC 606, Revenue from Contracts with Customers . Under this new standard, an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The FASB also issued several updates to ASU 2014-09. We elected to early adopt this standard and to apply its provisions as of January 1, 2017 to all open contracts existing as of that date using the modified retrospective approach. We determined that the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings was immaterial. Further, our adoption of the new standard did not have a material impact on any balance sheet or income statement line items in the period of adoption and, as such, we did not record any adjustments to the consolidated financial statements related to our adoption of this standard. Disaggregated revenue Revenue disaggregated by type of service was as follows for the periods presented: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Merchant fees $ 82,909 $ 63,934 $ 217,850 $ 169,702 Interchange fees 13,861 12,236 40,057 32,841 Transaction fees 96,770 76,170 257,907 202,543 Servicing fees 17,101 12,071 46,890 33,245 Other (1) 41 75 145 285 Servicing and other 17,142 12,146 47,035 33,530 Total revenue $ 113,912 $ 88,316 $ 304,942 $ 236,073 (1) Other revenue includes miscellaneous revenue items that are individually immaterial. Other revenue is presented separately herein in order to clearly present merchant, interchange and servicing fees, which are more integral to our primary operations and better enable financial statement users to calculate metrics such as servicing and merchant fee yields. We have no remaining performance obligations as of September 30, 2018 . No assets were recognized from the costs to obtain or fulfill a contract with a customer as of September 30, 2018 or December 31, 2017 . Recognition and measurement of financial assets and financial liabilities In January 2016, the FASB issued ASU 2016-01 to address certain aspects of recognition, measurement, presentation and disclosure of financial instruments. We adopted the standard for the reporting period beginning January 1, 2018. As a result of adopting the standard, we eliminated the disclosure requirement of the methods and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet, which applies to our fair value of term loan disclosure in Note 3. The remaining provisions of the standard were either not applicable to us or already satisfied in our disclosures. Therefore, our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Improvements to employee share-based payment accounting In March 2016, the FASB issued ASU 2016-09 to simplify certain aspects of the accounting for share-based payment transactions. Under the new standard, all excess tax benefits and tax deficiencies should be recognized as income tax benefit or expense, respectively, in the income statement when stock awards vest or are settled. In addition, the standard eliminates the requirement to reclassify cash flows related to excess tax benefits from operating activities to financing activities on the statements of cash flows, increases the threshold for withholding an employee’s vested shares for tax withholding purposes without triggering liability accounting and clarifies that cash payments made by an employer to tax authorities on an employee’s behalf when directly withholding shares for tax withholding purposes should be presented as a financing activity on the statement of cash flows. The standard also provides an accounting policy election to account for forfeitures as they occur rather than to estimate the number of awards that are expected to vest. We adopted the standard for the reporting period beginning January 1, 2017. The provisions related to excess tax benefits or deficiencies from share-based award activity became applicable for us following the IPO and Reorganization Transactions. We also elected to retain our existing accounting policy election to estimate award forfeitures. Our adoption of this standard did not have a material impact on our Unaudited Consolidated Financial Statements. Scope of modification accounting In May 2017, the FASB issued ASU 2017-09 to provide clarity and reduce both diversity in practice and the cost and complexity to an entity when applying the guidance in ASC 718, Compensation—Stock Compensation, to a change in the terms or conditions of a share-based payment award. The standard provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. We adopted the standard for the reporting period beginning January 1, 2018, and will apply its provisions prospectively to any award modified on or after the adoption date. Our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Disclosure framework - changes to the disclosure requirements for fair value measurement In August 2018, the FASB issued ASU 2018-13 to modify certain disclosure requirements about recurring and nonrecurring fair value measurements to improve disclosure effectiveness. We adopted the standard for the reporting period beginning July 1, 2018. As a result of adopting this standard, we replaced our previously disclosed quantitative sensitivity analyses for unobservable inputs used to develop our Level 3 fair value measurements with narrative descriptions of the uncertainty of our fair value measurements to changes in unobservable inputs, and added explanations of how we calculated the weighted averages of the significant unobservable inputs used to develop our Level 3 fair value measurements. Our adoption of this standard did not have any impact on our Unaudited Consolidated Financial Statements. Accounting Standards Issued, But Not Yet Adopted Leases In February 2016, the FASB issued ASU 2016-02, which requires lessees to recognize leases with terms greater than twelve months on the balance sheet as right-of-use assets and corresponding liabilities. Lessees will continue to classify leases as either operating leases, using a straight-line expense pattern, or financing leases, using a front-loaded expense pattern. The standard also requires enhanced quantitative and qualitative disclosures related to the lease arrangements. The standard is effective for us on January 1, 2019, with early adoption permitted, using a modified retrospective approach. We are evaluating the potential impact of adopting this standard by reviewing our existing lease contracts, all of which are operating leases wherein the Company is the lessee. For the future minimum lease payments of $16.8 million as of September 30, 2018 required under our existing operating leases (as disclosed in Note 12) and for other similar leases we may enter into prior to adopting this standard, we expect to gross up our Unaudited Consolidated Balance Sheets at their present values to recognize the right-of-use assets and lease liabilities. The quantitative impact of adopting this standard remains under evaluation; however, we do not expect material changes to the recognition, measurement and presentation of rent expense, which is included within property, office and technology expenses and related party expenses in our Unaudited Consolidated Statements of Operations. Similarly, we do not expect a material impact to our Unaudited Consolidated Statements of Cash Flows. In July 2018, the FASB issued ASU 2018-10, which clarifies certain aspects of the guidance issued in ASU 2016-02. Upon adoption of this standard, we, as the lessee, will be required to reassess lease classification upon modification based on the facts and circumstances and the modified terms and conditions, if applicable, as of the date of reassessment. The remaining provisions of the standard are either not applicable to us or already satisfied in our disclosures. The standard is effective for us on January 1, 2019, with early adoption permitted, using a modified retrospective approach. We are currently evaluating the potential impact of adopting this standard; however, we do not expect material changes to the classification of leases or to the recognition of rent expense. In July 2018, the FASB issued ASU 2018-11, which provides an additional (and optional) transition method to adopt ASU 2016-02 by applying its provisions at the adoption date and recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, rather than applying the provisions of ASU 2016-02 at the beginning of the earliest period presented in the financial statements. Entities that elect this additional transition method must provide the required ASC 840, Leases , disclosures for all periods that continue to be in accordance with ASC 840. The remaining provisions of the standard are not applicable to us, as the provisions relate only to lessors. The standard is effective for us on January 1, 2019 in conjunction with our adoption of ASU 2016-02. Measurement of credit losses on financial instruments In June 2016, the FASB issued ASU 2016-13, which is intended to better align the timing of recognition of credit losses on financial instruments with management’s expectations. The standard requires a financial asset (or group of financial assets) measured at amortized cost to be presented at the net amount expected to be collected. Management must determine expected credit losses for all financial instruments held at the reporting date based on relevant information about past events, including historical experience, current conditions and reasonable and supportable forecasts, the latter of which broadens current guidance. The standard requires enhanced disclosures to help investors and other financial statement users to better understand the significant estimates and judgments used in estimating credit losses. The standard is effective for us on January 1, 2020, with early adoption permitted, but not before January 1, 2019. The majority of this standard's provisions must be applied using a modified retrospective approach. We are currently evaluating the potential impact of adopting this standard. Improvements to nonemployee share-based payment accounting In June 2018, the FASB issued ASU 2018-07 to simplify certain aspects of the accounting for non-employee share-based payment transactions. Under the new standard, all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor's own operations by issuing share-based payment awards are within the scope of ASC 718. Consistent with the accounting requirement for employee share-based payment awards, non-employee share-based payment awards within the scope of ASC 718 are measured at grant-date fair value of the equity instruments, and the requirement to reassess classification of non-employee share-based payment awards upon vesting is eliminated. The standard is effective for us on January 1, 2019, with early adoption permitted, using a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption to remeasure equity-classified awards for which a measurement date has not been established and liability-classified awards that have not been settled by the date of adoption. We are currently evaluating the potential impact of adopting this standard; however, we do not expect adoption to have a material impact, as the Company has a limited number of non-employee share-based payment transactions outstanding and does not anticipate material non-employee share-based payment transactions in the future. Customer's accounting for implementation costs incurred in a cloud computing arrangement that is a service contract In August 2018, the FASB issued ASU 2018-15, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Accordingly, costs for implementation activities in the application development stage are capitalized depending on the nature of the costs, while costs incurred during the preliminary project and post-implementation stages are expensed as the activities are performed. This standard also requires entities to amortize the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement and to apply the existing impairment guidance in ASC 350-40 to the capitalized implementation costs as if the costs were long-lived assets. The standard clarifies that such capitalized implementation costs are also subject to the guidance on abandonment in ASC 360, Property, Plant, and Equipment . In addition, this standard requires alignment in presentation between: (1) the expense related to the capitalized implementation costs and the fees associated with the hosting element (service) of the arrangement on the statement of operations, (2) the capitalized implementation costs and any prepayment for the fees of the associated hosting arrangement on the balance sheet, and (3) the payments for capitalized implementation costs and the payments made for fees associated with the hosting element in the statement of cash flows. The standard is effective for us on January 1, 2020, with early adoption permitted, and should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. We are refining our inventory of existing cloud computing arrangements to identify hosting arrangements that are service contracts and will evaluate how to account for the implementation costs of such arrangements.

Organization, Summary of Sign_3

Organization, Summary of Signifant Accounting Policies and New Accounting Standards (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of cash and cash equivalents	The following table provides a reconciliation of cash and restricted cash reported within the Unaudited Consolidated Balance Sheets to the total included within the Unaudited Consolidated Statements of Cash Flows as of the periods indicated. September 30, 2018 September 30, 2017 Cash $ 294,336 $ 105,293 Restricted cash 160,909 120,289 Cash and restricted cash in Unaudited Consolidated Statements of Cash Flows $ 455,245 $ 225,582
Schedule of restricted cash	The following table provides a reconciliation of cash and restricted cash reported within the Unaudited Consolidated Balance Sheets to the total included within the Unaudited Consolidated Statements of Cash Flows as of the periods indicated. September 30, 2018 September 30, 2017 Cash $ 294,336 $ 105,293 Restricted cash 160,909 120,289 Cash and restricted cash in Unaudited Consolidated Statements of Cash Flows $ 455,245 $ 225,582
Revenue disaggregated by type of service	Revenue disaggregated by type of service was as follows for the periods presented: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Merchant fees $ 82,909 $ 63,934 $ 217,850 $ 169,702 Interchange fees 13,861 12,236 40,057 32,841 Transaction fees 96,770 76,170 257,907 202,543 Servicing fees 17,101 12,071 46,890 33,245 Other (1) 41 75 145 285 Servicing and other 17,142 12,146 47,035 33,530 Total revenue $ 113,912 $ 88,316 $ 304,942 $ 236,073 (1) Other revenue includes miscellaneous revenue items that are individually immaterial. Other revenue is presented separately herein in order to clearly present merchant, interchange and servicing fees, which are more integral to our primary operations and better enable financial statement users to calculate metrics such as servicing and merchant fee yields.

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Basic and diluted earnings per share	The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for the three and nine months ended September 30, 2018 . The basic and diluted earnings per share for the nine months ended September 30, 2018 represents only the period from May 24, 2018 to September 30, 2018 , the period wherein we had outstanding Class A common stock. Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 Numerator: Income before income tax expense $ 49,087 $ 110,101 Less: Net income attributable to GS Holdings prior to the Reorganization Transactions — 38,213 Less: Net income attributable to noncontrolling interests subsequent to the Reorganization Transactions 33,711 49,368 Less: Income tax expense 3,375 4,969 Net income attributable to GreenSky, Inc. - basic $ 12,001 $ 17,551 Add: Reallocation of net income attributable to noncontrolling interests after the Reorganization Transactions from the assumed exchange of common units of GS Holdings for Class A common stock 33,711 49,368 Less: Income tax expense on reallocation of net income attributable to noncontrolling interests (1) 7,400 10,893 Net income attributable to GreenSky, Inc. - diluted $ 38,312 $ 56,026 Denominator: Weighted average shares of Class A common stock outstanding - basic 57,412,673 57,408,861 Add: Dilutive effects as shown separately below Holdco Units exchangeable for Class A common stock 128,052,758 128,155,169 Class A common stock options 2,813,764 2,646,827 Holdco warrants exchangeable for Class A common stock 707,414 635,436 Unvested Class A common stock (2) 169,315 179,339 Weighted average shares of Class A common stock outstanding - diluted 189,155,924 189,025,632 Earnings per share of Class A common stock outstanding - basic $ 0.21 $ 0.31 Earnings per share of Class A common stock outstanding - diluted (3)(4) $ 0.20 $ 0.30 (1) For the three and nine months ended September 30, 2018 periods, we assumed effective tax rates of 22.0% and 22.1% , respectively. (2) Includes both Class A common stock issued as part of the Reorganization Transactions and unvested Class A common stock awards issued subsequent to the Reorganization Transactions. (3) Year-to-date results do not agree to the sum of individual quarter-to-date results due to rounding. (4) Our calculation of diluted earnings per share excludes 1,184,029 Class A common stock options and 134,170 unvested Class A common stock awards for the three and nine months ended September 30, 2018 , as their inclusion would have been anti-dilutive. These amounts represent the number of instruments outstanding at the end of the period. Application of the treasury stock method would reduce these amounts if they had a dilutive effect and were included in the computation of diluted earnings per share. Shares of the Company’s Class B common stock do not participate in the earnings or losses of the Company and, therefore, are not participating securities. As such, separate presentation of basic and diluted earnings per share of Class B common stock under the two-class method has not been presented.

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Charged-Off Receivable transfers	The following table presents details of Charged-Off Receivables transfers during the periods indicated. Aggregate Unpaid Balance Proceeds Bank Partner loans Loan receivables held for sale Total (1) Bank Partner loans Loan receivables held for sale Total Three months ended September 30, 2018 $ 67,455 $ 841 $ 68,296 $ 9,039 $ 113 $ 9,152 Three months ended September 30, 2017 73,494 1,061 74,555 5,914 86 6,000 Nine months ended September 30, 2018 142,350 2,124 144,474 19,039 284 19,323 Nine months ended September 30, 2017 73,494 1,061 74,555 5,914 86 6,000 (1) During the three and nine months ended September 30, 2018 , $3,952 and $10,632 , respectively, of the aggregate unpaid balance on cumulative transferred Charged-Off Receivables were recovered through our servicing efforts on behalf of our Charged-Off Receivables investors. During the three and nine months ended September 30, 2017 , such recoveries totaled $498 and $498 , respectively.
Carrying amounts and estimated fair values of assets and liabilities measured at fair value on a recurring or nonrecurring basis	The following table summarizes, by level within the fair value hierarchy, the carrying amounts and estimated fair values of our assets and liabilities measured at fair value on a recurring or nonrecurring basis or disclosed, but not carried, at fair value in the Unaudited Consolidated Balance Sheets as of the dates presented. There were no transfers into, out of, or between levels within the fair value hierarchy during any of the periods presented. Refer to Note 4, Note 7 and Note 8 for additional information on these assets and liabilities. Level September 30, 2018 December 31, 2017 Carrying Fair Value Carrying Value Fair Value Assets: Loan receivables held for sale, net (1) 2 $ 14,765 $ 15,459 $ 73,606 $ 74,190 Liabilities: Finance charge reversal liability (2) 3 $ 117,202 $ 117,202 $ 94,148 $ 94,148 Servicing liabilities (2) 3 2,692 2,692 2,071 2,071 Term loan (3) 2 387,401 397,073 338,263 345,820 (1) Measured at fair value on a nonrecurring basis. (2) Measured at fair value on a recurring basis. Servicing liabilities are presented within other liabilities in the Unaudited Consolidated Balance Sheets. The cash flow impacts of our liabilities that are measured at fair value on a recurring basis are included within net cash provided by operating activities in the Unaudited Consolidated Statements of Cash Flows. (3) Disclosed, but not carried, at fair value. The amounts disclosed as of September 30, 2018 relate to the modified term loan and amounts disclosed as of December 31, 2017 relate to the original term loan. Refer to Note 7 for additional information. The carrying value of our term loan is net of unamortized debt discount and debt issuance costs. The fair value of our term loan was determined using a discounted cash flow model based on observable market factors (such as changes in credit spreads for comparable benchmark companies) and credit factors specific to us.
Reconciliation of the beginning and ending fair value measurements of FCR Liability	The following table reconciles the beginning and ending fair value measurements of our FCR liability, which is classified as Level 3 within the fair value hierarchy due to the use of unobservable inputs, during the periods indicated. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 107,047 $ 76,319 $ 94,148 $ 68,064 Receipts (1) 38,520 30,675 100,355 75,014 Settlements (2) (47,211 ) (33,830 ) (136,883 ) (95,363 ) Fair value changes recognized in cost of revenue (3) 18,846 9,588 59,582 35,037 Ending balance $ 117,202 $ 82,752 $ 117,202 $ 82,752 (1) Represents cash received from deferred payment loans during the promotional period (incentive payments), as well as the proceeds received from transferring our rights to Charged-Off Receivables attributable to previously charged-off Bank Partner loans. We consider all monthly incentive payments from Bank Partners during the period to be related to billed finance charges on deferred interest products until monthly incentive payments exceed total billed finance charges on deferred products, which did not occur during any of the periods presented. (2) Represents the reversal of previously billed finance charges associated with deferred payment loan principal balances that paid off within the promotional period. (3) A fair value adjustment is made based on the expected reversal percentage of billed finance charges (expected settlements), which is estimated at each reporting period. The fair value adjustment is recognized in cost of revenue in the Unaudited Consolidated Statements of Operations.
Significant unobservable inputs used to value Level 3 FCR liability	The following table presents the estimated reversal rate for billed interest on deferred loan products, which is the significant unobservable input used to value the Level 3 FCR liability, as of the dates indicated. Reversal rate September 30, 2018 December 31, 2017 Range 80.5% – 98.0% 85.5% – 98.0% Weighted average 88.9 % 89.0 %
Servicing liabilities and unobservable inputs	The following table reconciles the beginning and ending fair value measurements of our servicing liabilities associated with transferring our rights to Charged-Off Receivables, which are classified as Level 3 within the fair value hierarchy due to the use of unobservable inputs, during the periods presented. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 2,272 $ — $ 2,071 $ — Initial obligation from transfer of Charged-Off Receivables (1) 826 886 1,737 886 Fair value changes recognized in other gains/(losses) Change in inputs or assumptions used in the valuation model — — — — Other changes in fair value (1)(2) (406 ) (86 ) (1,116 ) (86 ) Ending balance $ 2,692 $ 800 $ 2,692 $ 800 (1) Recognized in other gains/(losses) in the Unaudited Consolidated Statements of Operations. (2) Represents the reduction of our servicing liability due to the passage of time and collection of loan payments. The following table presents quantitative information about the significant unobservable inputs used to value the Level 3 servicing liabilities as of the dates presented. Input September 30, 2018 December 31, 2017 Range Weighted Average Range Weighted Average Cost of servicing (basis points) 62.5 62.5 62.5 62.5 Discount rate 18.0 % 18.0 % 18.0 % 18.0 % Recovery period (years) 3.8 – 4.9 4.4 4.6 – 4.9 4.8

Loan Receivables Held for Sale

Loan Receivables Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Activity in the balance of loan receivables held for sale	The following table summarizes the activity in the balance of loan receivables held for sale at lower of cost or fair value during the periods indicated. Nine Months Ended 2018 2017 Beginning balance $ 73,606 $ 41,268 Additions 70,805 104,573 Proceeds from sales and customer payments (1) (126,981 ) (33,554 ) Loss on sale — (88 ) Decrease/(increase) in valuation allowance (110 ) — Transfers (2) 22 (4,956 ) Write offs and other (3) (2,577 ) (2,393 ) Ending balance $ 14,765 $ 104,850 (1) Customer payments include accrued interest and fees, recoveries of previously charged-off loan receivables held for sale, as well as proceeds from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. We retain servicing arrangements on sold loan receivables with the same terms and conditions as loans that are originated by our Bank Partners. Income from loan receivables held for sale activities is recorded within interest income and other gains/(losses) in the Unaudited Consolidated Statements of Operations. We sold loan receivables held for sale to certain Bank Partners on the following dates during the nine months ended September 30, 2018 and 2017 : 2018 Amount 2017 Amount May 21 $ 9,552 June 29 $ 17,900 June 27 50,614 September 27 48,176 Total $ 108,342 Total $ 17,900 (2) We temporarily hold certain loan receivables, which are originated by a Bank Partner, while non-originating Bank Partner eligibility is being determined. Once we determine that a loan receivable meets the investment requirements of an eligible Bank Partner, we transfer the loan to the Bank Partner at cost plus any accrued interest. The reported amount also includes loans that have been placed on non-accrual and non-payment status while we investigate consumer loan balance inquiries. (3) We received recovery payments of $9 and $29 during the three months ended September 30, 2018 and 2017 , respectively, and $42 and $218 during the nine months ended September 30, 2018 and 2017 , respectively, which are included within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Separately, during the three months ended September 30, 2018 and 2017 , write offs and other were reduced by $113 and $86 , respectively, related to cash proceeds received from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. During the nine months ended September 30, 2018 and 2017 , write offs and other were reduced by $284 and $86 , respectively, related to such cash proceeds. The cash proceeds received were recorded within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Accounts receivable consisted of the following as of the dates indicated. Accounts Receivable, Gross Allowance for Losses Accounts Receivable, Net September 30, 2018 Transaction related $ 17,605 $ (369 ) $ 17,236 Servicing related 1,387 — 1,387 Total $ 18,992 $ (369 ) $ 18,623 December 31, 2017 Transaction related $ 15,997 $ (276 ) $ 15,721 Servicing related 2,637 — 2,637 Total $ 18,634 $ (276 ) $ 18,358
Activities associated with loan receivable sales and servicing activities	The following table presents activities associated with our loan receivable sales and servicing activities during the periods indicated. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Gain/(loss) on sold loan receivables held for sale $ — $ — $ — $ (88 ) Cash Flows Sales of loans $ 48,176 $ — $ 108,342 $ 17,900 Servicing fees 546 550 1,645 2,261
Principal balances of sold loan receivables	The following table presents information about the principal balances of sold loan receivables that are not recorded in our Unaudited Consolidated Balance Sheets, but with which we have a continuing involvement through our servicing arrangements with our Bank Partners. The sold loan receivables are pooled with other loans originated by the Bank Partners for purposes of determining escrow balances and incentive payments. The escrow balances represent our only direct exposure to potential losses associated with these sold loan receivables. September 30, 2018 December 31, 2017 Total principal balance $ 350,296 $ 305,748 Delinquent loans (unpaid principal balance) 24,841 20,409 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net charge-offs (unpaid principal balance) $ 2,017 $ 2,265 $ 6,729 $ 5,270

Accounts Receivable (Tables)

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Activity in the balance of loan receivables held for sale	The following table summarizes the activity in the balance of loan receivables held for sale at lower of cost or fair value during the periods indicated. Nine Months Ended 2018 2017 Beginning balance $ 73,606 $ 41,268 Additions 70,805 104,573 Proceeds from sales and customer payments (1) (126,981 ) (33,554 ) Loss on sale — (88 ) Decrease/(increase) in valuation allowance (110 ) — Transfers (2) 22 (4,956 ) Write offs and other (3) (2,577 ) (2,393 ) Ending balance $ 14,765 $ 104,850 (1) Customer payments include accrued interest and fees, recoveries of previously charged-off loan receivables held for sale, as well as proceeds from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. We retain servicing arrangements on sold loan receivables with the same terms and conditions as loans that are originated by our Bank Partners. Income from loan receivables held for sale activities is recorded within interest income and other gains/(losses) in the Unaudited Consolidated Statements of Operations. We sold loan receivables held for sale to certain Bank Partners on the following dates during the nine months ended September 30, 2018 and 2017 : 2018 Amount 2017 Amount May 21 $ 9,552 June 29 $ 17,900 June 27 50,614 September 27 48,176 Total $ 108,342 Total $ 17,900 (2) We temporarily hold certain loan receivables, which are originated by a Bank Partner, while non-originating Bank Partner eligibility is being determined. Once we determine that a loan receivable meets the investment requirements of an eligible Bank Partner, we transfer the loan to the Bank Partner at cost plus any accrued interest. The reported amount also includes loans that have been placed on non-accrual and non-payment status while we investigate consumer loan balance inquiries. (3) We received recovery payments of $9 and $29 during the three months ended September 30, 2018 and 2017 , respectively, and $42 and $218 during the nine months ended September 30, 2018 and 2017 , respectively, which are included within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Separately, during the three months ended September 30, 2018 and 2017 , write offs and other were reduced by $113 and $86 , respectively, related to cash proceeds received from transferring our rights to Charged-Off Receivables attributable to loan receivables held for sale. During the nine months ended September 30, 2018 and 2017 , write offs and other were reduced by $284 and $86 , respectively, related to such cash proceeds. The cash proceeds received were recorded within other income/(expense), net in the Unaudited Consolidated Statements of Operations. Accounts receivable consisted of the following as of the dates indicated. Accounts Receivable, Gross Allowance for Losses Accounts Receivable, Net September 30, 2018 Transaction related $ 17,605 $ (369 ) $ 17,236 Servicing related 1,387 — 1,387 Total $ 18,992 $ (369 ) $ 18,623 December 31, 2017 Transaction related $ 15,997 $ (276 ) $ 15,721 Servicing related 2,637 — 2,637 Total $ 18,634 $ (276 ) $ 18,358

Property, Equipment and Softw_2

Property, Equipment and Software (Tables)	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Property, Equipment and Software	Property, equipment and software were as follows as of the dates indicated. September 30, 2018 December 31, 2017 Furniture $ 2,813 $ 2,704 Leasehold improvements 4,114 3,659 Computer hardware 3,012 2,987 Software 7,244 4,836 Total property, equipment and software, at cost 17,183 14,186 Less: accumulated depreciation (5,162 ) (4,060 ) Less: accumulated amortization (2,253 ) (2,278 ) Total property, equipment and software, net $ 9,768 $ 7,848

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Key details of the term loans	Key details of the term loans are as follows: September 30, 2018 (1) December 31, 2017 (1) Term loan, face value (2) $ 398,000 $ 349,125 Unamortized debt discount (3) (3,882 ) (3,321 ) Unamortized debt issuance costs (3) (6,717 ) (7,541 ) Term loan $ 387,401 $ 338,263 (1) Amounts reported reflect details of the original term loan as of December 31, 2017 , and details of the modified term loan as of September 30, 2018 . (2) The principal balance of the original term loan was scheduled to be repaid on a quarterly basis at an amortization rate of 0.25% per quarter. We made the first principal payment in December 2017. The principal balance of the modified term loan is scheduled to be repaid on a quarterly basis at an amortization rate of 0.25% per quarter, with the balance due at maturity. We made the first principal payment on the modified term loan in June 2018. For each of the next five years, principal repayments on the modified term loan are expected to be $4,000 . (3) For the three months ended September 30, 2018 and 2017 , $155 and $52 of debt discount and $267 and $119 of debt issuance costs, respectively, were amortized into interest expense in the Unaudited Consolidated Statements of Operations. For the nine months ended September 30, 2018 and 2017 , $438 and $52 of debt discount and $824 and $119 of debt issuance costs, respectively, were amortized into interest expense in the Unaudited Consolidated Statements of Operations.

Other Liabilities (Tables)

Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Other Liabilities Disclosure [Abstract]
Other Liabilities	The following table details the components of other liabilities in the Unaudited Consolidated Balance Sheets as of the dates indicated. September 30, 2018 December 31, 2017 Deferred lease liabilities $ 2,618 $ 2,819 Transaction processing liabilities 18,741 16,435 Servicing liabilities (1) 2,692 2,071 Distributions payable (2) 10,565 13,189 Accruals and other liabilities 5,033 4,327 Total other liabilities $ 39,649 $ 38,841 (1) Refer to Note 3 for additional information on servicing liabilities. (2) Related party distributions payable are not included in this balance, but rather are included within related party liabilities.

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation, Stock Options, Activity	Class A common stock option ("Options") activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Number of Options Weighted Average Exercise Price Number of Options Outstanding at beginning of period 9,821,884 $ 2.65 10,006,890 Granted prior to Reorganization Transactions and IPO (1) 340,000 14.95 450,000 Exercised prior to Reorganization Transactions and IPO (2)(3) (270,000 ) 3.19 (202,000 ) Forfeited prior to Reorganization Transactions and IPO (260,000 ) 6.41 (400,500 ) Effect of Reorganization Transactions and IPO (186,772 ) 7.56 N/A Granted after the Reorganization Transactions and IPO (1) 1,014,029 21.72 N/A Exercised after Reorganization Transactions and IPO (3) (42,000 ) 1.39 N/A Forfeited after Reorganization Transactions and IPO (202,000 ) 19.34 N/A Outstanding at end of period (4) 10,215,141 $ 4.43 9,854,390 Exercisable at end of period (4) 7,237,582 $ 1.54 6,718,500 (1) Weighted average grant date fair value of Options granted during the nine months ended September 30, 2018 and 2017 was $6.29 and $3.42 , respectively. (2) The total intrinsic value of Options exercised, which is defined as the amount by which the market value of the stock on the date of exercise exceeds the exercise price, during the nine months ended September 30, 2018 and 2017 was $1,475 and $396 , respectively. (3) Employees paid $339 during the nine months ended September 30, 2018 to the Company to exercise Options, which resulted in the issuance of 30,516 Holdco Units prior to the Reorganization Transactions and IPO. Additionally, during the nine months ended September 30, 2018 , 252,000 Options were exercised by means of a cashless net exercise procedure, which resulted in the issuance of 38,637 Holdco Units prior to the Reorganization Transactions and IPO and the issuance of 9,964 shares of Class A common stock subsequent to the Reorganization Transactions and IPO. (4) The aggregate intrinsic value and weighted average remaining contractual terms of Options outstanding and Options exercisable were as follows as of September 30, 2018 : September 30, 2018 Aggregate intrinsic value (in millions) Unit Options outstanding $ 56.1 Unit Options exercisable $ 45.7 Weighted average remaining term (in years) Unit Options outstanding 5.42 Unit Options exercisable 4.41
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value	The aggregate intrinsic value and weighted average remaining contractual terms of Options outstanding and Options exercisable were as follows as of September 30, 2018 : September 30, 2018 Aggregate intrinsic value (in millions) Unit Options outstanding $ 56.1 Unit Options exercisable $ 45.7 Weighted average remaining term (in years) Unit Options outstanding 5.42 Unit Options exercisable 4.41
Schedule of Other Share-based Compensation, Activity	Profits interests activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Number of Weighted Number of Outstanding at beginning of period 14,061,530 $ 8.23 12,616,890 Granted prior to Reorganization Transactions and IPO (1) 2,920,000 14.31 420,000 Forfeited prior to Reorganization Transactions and IPO (800,000 ) 9.32 (880,000 ) Redeemed prior to Reorganization Transactions and IPO — N/A — Effect of Reorganization Transactions and IPO (16,181,530 ) 9.27 N/A Outstanding at end of period (2) — N/A 12,156,890 (1) Weighted average grant date fair value of profits interests granted during the nine months ended September 30, 2018 and 2017 was $4.47 and $2.71 , respectively. (2) The total fair value based on grant date fair value of profits interests that vested was $371 and $1,204 during the nine months ended September 30, 2018 and 2017 , respectively.
Schedule of Nonvested Share Activity	Unvested Holdco Units activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Holdco Units Weighted Average Grant Date Fair Value Holdco Units Unvested at beginning of period — N/A N/A Effect of Reorganization Transactions and IPO 3,172,843 $ 23.00 N/A Granted — N/A N/A Forfeited (156,739 ) 23.00 N/A Vested (1) (118,082 ) 23.00 N/A Unvested at end of period 2,898,022 $ 23.00 N/A (1) The total fair value, based on grant date fair value, of previously unvested Holdco Units that vested during the nine months ended September 30, 2018 was $2,716 . Unvested Class A common stock award activity was as follows during the periods indicated: Nine Months Ended Nine Months Ended Class A common stock Weighted Average Grant Date Fair Value Class A common stock Unvested at beginning of period — N/A N/A Effect of Reorganization Transactions and IPO 255,904 $ 23.00 N/A Granted 137,170 19.71 N/A Forfeited — N/A N/A Vested (1) (15,049 ) 23.00 N/A Unvested at end of period 378,025 $ 21.81 N/A (1) The total fair value, based on grant date fair value, of previously unvested Class A common stock awards that vested during the nine months ended September 30, 2018 was $346 .

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	As of September 30, 2018 , future minimum lease payments under our leases for the periods presented are as follows: September 30, 2018 Remainder of 2018 $ 907 2019 3,725 2020 3,815 2021 3,878 2022 2,827 2023 and thereafter 1,647 Total minimum lease payments $ 16,799

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	Unaudited Consolidated Balance Sheets effects associated with our related party financing partners were as follows at the dates indicated: September 30, 2018 December 31, 2017 Related party receivables (1) $ — $ 8 Related party liabilities (2) — 445 Restricted cash — 437 (1) Receivables related to servicing and other. (2) Related party liabilities primarily consisted of related party servicing payables. Unaudited Consolidated Statements of Operations effects associated with our related party financing partners were as follows during the periods indicated and include the income related impact of our two previous related party financing arrangements that were terminated in June 2018 and June 2017, respectively. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Servicing and other $ — $ 32 $ 54 $ 248 Related party expenses (1) — — — 69 (1) Expenses incurred related to related party financing partner credit losses.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Variable Interest Entities	Below are tabular disclosures that provide insight into how GS Holdings affects GreenSky, Inc.’s financial position, performance and cash flows. Prior to the IPO and Reorganization Transactions, GreenSky, Inc. was not impacted by GS Holdings and, therefore, 2017 periods are not presented below. The following table presents the balances related to GS Holdings that are included in the Unaudited Consolidated Balance Sheets, as well as GreenSky, Inc.'s interest in the variable interest entity ("VIE") at September 30, 2018 . September 30, 2018 Assets Cash $ 285,310 Restricted cash 160,909 Loan receivables held for sale, net 14,765 Accounts receivable, net 18,623 Related party receivables 122 Property, equipment and software, net 9,768 Other assets 4,989 Total assets $ 494,486 Liabilities and Members Equity (Deficit) Liabilities Accounts payable $ 6,134 Accrued compensation and benefits 5,525 Other accrued expenses 1,013 Finance charge reversal liability 117,202 Term loan 387,401 Related party liabilities 937 Other liabilities 39,649 Total liabilities 557,861 Members Equity (Deficit) Equity (deficit) attributable to Continuing LLC Members (41,533 ) Equity (deficit) attributable to GreenSky, Inc. (21,842 ) Total members equity (deficit) (63,375 ) Total liabilities and members equity (deficit) $ 494,486 The following table reflects the impact of consolidation of GS Holdings into the Unaudited Consolidated Statements of Operations for the three and nine months ended September 30, 2018 . Three Months Ended September 30, Nine Months Ended September 30, 2018 2018 Total operating revenue $ 113,912 $ 304,942 Total operating expenses 59,655 180,300 Operating profit 54,257 124,642 Total other income/(expense), net (5,170 ) (14,541 ) Net income $ 49,087 $ 110,101 The following table reflects the cash flow impact of GS Holdings on the Unaudited Consolidated Statement of Cash Flows during the nine months ended September 30, 2018 : Nine Months Ended September 30, 2018 Net cash provided by operating activities $ 203,421 Net cash used in investing activities (4,849 ) Net cash used in financing activities (106,191 ) Net increase in cash and restricted cash 92,381 Cash and restricted cash at beginning of period 353,838 Cash and restricted cash at end of period $ 446,219

Organization, Summary of Sign_4

Organization, Summary of Signifant Accounting Policies and New Accounting Standards - Narrative (Details)	May 24, 2018USD ($)$ / sharesshares	Sep. 30, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)$ / shares
Subsidiary, Sale of Stock [Line Items]
Remaining performance obligations		$ 0
Capitalized contract cost		0	$ 0
Future minimum lease payments		$ 16,799,000
Class B common stock
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Class A common stock
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Class A common stock | IPO
Subsidiary, Sale of Stock [Line Items]
Number of shares sold | shares	43,700,000
Price per share (in dollars per share) | $ / shares	$ 23
Net proceeds, after deducting underwriting discounts and commissions	$ 954,800,000
GS Holdings | Class A common stock | Sale Of Stock To Parent Company [Member]
Subsidiary, Sale of Stock [Line Items]
Number Of Shares Purchased By Company | shares	2,426,198
GS Holdings | Newly-issued common units | Sale Of Stock To Parent Company [Member]
Subsidiary, Sale of Stock [Line Items]
Number Of Shares Purchased By Company | shares	41,273,802
Exchange of Holdco Units for Class A common stock pursuant to the Exchange Agreement
Subsidiary, Sale of Stock [Line Items]
Exchange ratio	1
GS Holdings
Subsidiary, Sale of Stock [Line Items]
Economic interest (as a percent)		31.30%

Organization, Summary of Sign_5

Organization, Summary of Signifant Accounting Policies and New Accounting Standards - Cash and restricted cash (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash	$ 294,336	$ 224,614	$ 105,293
Restricted cash	160,909	129,224	120,289
Cash and restricted cash in Unaudited Consolidated Statements of Cash Flows	$ 455,245	$ 353,838	$ 225,582	$ 228,114

Organization, Summary of Sign_6

Organization, Summary of Signifant Accounting Policies and New Accounting Standards - Revenue disaggregated by type of service (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 113,912	$ 88,316	$ 304,942	$ 236,073
Transaction fees
Disaggregation of Revenue [Line Items]
Total revenue	96,770	76,170	257,907	202,543
Merchant fees
Disaggregation of Revenue [Line Items]
Total revenue	82,909	63,934	217,850	169,702
Interchange fees
Disaggregation of Revenue [Line Items]
Total revenue	13,861	12,236	40,057	32,841
Servicing and other
Disaggregation of Revenue [Line Items]
Total revenue	17,142	12,146	47,035	33,530
Servicing fees
Disaggregation of Revenue [Line Items]
Total revenue	17,101	12,071	46,890	33,245
Other
Disaggregation of Revenue [Line Items]
Total revenue	$ 41	$ 75	$ 145	$ 285

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Income before income tax expense		$ 49,087	$ 38,162	$ 110,101	$ 98,766
Less: Net income attributable to GS Holdings prior to the Reorganization Transactions		0		38,213
Less: Net income attributable to noncontrolling interests subsequent to the Reorganization Transactions		33,711		49,368
Income tax expense		3,375	$ 0	4,969	$ 0
Net income attributable to GreenSky, Inc. - basic		12,001		17,551
Less: Income tax expense on reallocation of net income attributable to noncontrolling interests(1)		7,400		10,893
Net income attributable to GreenSky, Inc. - diluted		$ 38,312		$ 56,026
Denominator:
Weighted average shares of Class A common stock outstanding - basic (in shares)		57,412,673		57,408,861
Add: Dilutive effects as shown separately below
Holdco warrants exchangeable for Class A common stock (in shares)		707,414		635,436
Weighted average shares of Class A common stock outstanding - diluted (in shares)		189,155,924		189,025,632
Earnings per share of Class A common stock outstanding - basic (in dollars per share)	[1]	$ 0.21		$ 0.31
Earnings per share of Class A common stock outstanding - diluted (in dollars per share)	[1]	$ 0.20		$ 0.30
Effective income tax rate (as a percent)		22.00%		22.10%
HoldCo Units
Add: Dilutive effects as shown separately below
Holdco Units that are exchangeable for Class A common stock (in shares)		128,052,758		128,155,169
Class A common stock
Add: Dilutive effects as shown separately below
Dilutive effect of share based compensation awards (in shares)		2,813,764		2,646,827
Antidilutive securities excluded from computation of earnings per share (in shares)		1,184,029		1,184,029
Unvested Class A stock awards
Add: Dilutive effects as shown separately below
Dilutive effect of share based compensation awards (in shares)		169,315		179,339
Antidilutive securities excluded from computation of earnings per share (in shares)		134,170		134,170
[1]	Basic and diluted earnings per share of Class A common stock is applicable only for the period from May 24, 2018 through September 30, 2018, which is the period following the initial public offering ("IPO") and related Reorganization Transactions (as defined in Note 1 to the Unaudited Consolidated Financial Statements). See Note 2, Earnings per Share, for the number of shares used in the computation of earnings per share of Class A common stock and the basis for the computation of earnings per share.

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Charged-Off Receivable transfers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Transfer of Financial Assets Accounted for as Sales [Line Items]
Aggregate Unpaid Balance	$ 68,296	$ 74,555	$ 144,474	$ 74,555
Proceeds	9,152	6,000	19,323	6,000
Amount recovered on transferred Charged-Off Receivables	3,952	498	10,632	498
Bank Partner loans
Transfer of Financial Assets Accounted for as Sales [Line Items]
Aggregate Unpaid Balance	67,455	73,494	142,350	73,494
Proceeds	9,039	5,914	19,039	5,914
Loan receivables held for sale
Transfer of Financial Assets Accounted for as Sales [Line Items]
Aggregate Unpaid Balance	841	1,061	2,124	1,061
Proceeds	$ 113	$ 86	$ 284	$ 86

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Carrying amounts and estimated fair values of assets and liabilities measured at fair value on a recurring or nonrecurring basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Liabilities:
Finance charge reversal liability	$ 117,202	$ 94,148
Carrying Value | Measured at fair value on a nonrecurring basis | Level 2
Assets:
Loan receivables held for sale, net	14,765	73,606
Carrying Value | Measured at fair value on a recurring basis | Level 2
Liabilities:
Term loan	387,401	338,263
Carrying Value | Measured at fair value on a recurring basis | Level 3
Liabilities:
Finance charge reversal liability	117,202	94,148
Servicing liability	2,692	2,071
Fair Value | Measured at fair value on a nonrecurring basis | Level 2
Assets:
Loan receivables held for sale, net	15,459	74,190
Fair Value | Measured at fair value on a recurring basis | Level 2
Liabilities:
Term loan	397,073	345,820
Fair Value | Measured at fair value on a recurring basis | Level 3
Liabilities:
Finance charge reversal liability	117,202	94,148
Servicing liability	$ 2,692	$ 2,071

Fair Value of Assets and Liab_5

Fair Value of Assets and Liabilities - Reconciliation of the beginning and ending fair value measurements of FCR Liability (Details) - Finance charge reversals - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation
Beginning balance	$ 107,047	$ 76,319	$ 94,148	$ 68,064
Receipts	38,520	30,675	100,355	75,014
Settlements	(47,211)	(33,830)	(136,883)	(95,363)
Fair value changes recognized in cost of revenue	18,846	9,588	59,582	35,037
Ending balance	$ 117,202	$ 82,752	$ 117,202	$ 82,752

Fair Value of Assets and Liab_6

Fair Value of Assets and Liabilities - Significant unobservable inputs used to value Level 3 FCR liability (Details)	Sep. 30, 2018	Dec. 31, 2017
Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Reversal rate	0.805	0.855
Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Reversal rate	0.980	0.980
Weighted average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Reversal rate	0.889	0.890

Fair Value of Assets and Liab_7

Fair Value of Assets and Liabilities - Additional information (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Period after which collection efforts will cease	5 years
Servicing liabilities	$ 2,692	$ 2,272	$ 2,071	$ 800	$ 0	$ 0

Fair Value of Assets and Liab_8

Fair Value of Assets and Liabilities - Servicing liabilities and unobservable inputs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Servicing Liability at Fair Value, Amount
Beginning balance	$ 2,272	$ 0	$ 2,071	$ 0	$ 0
Initial obligation from transfer of Charged-Off Receivables	826	886	1,737	886
Change in inputs or assumptions used in the valuation model	0	0	0	0
Other changes in fair value	(406)	(86)	(1,116)	(86)
Ending balance	$ 2,692	$ 800	$ 2,692	$ 800	$ 2,071
Servicing Liabilities at Fair Value [Line Items]
Cost of servicing (basis points)			0.625%		0.625%
Discount rate			18.00%		18.00%
Weighted Average
Servicing Liabilities at Fair Value [Line Items]
Cost of servicing (basis points)			0.625%		0.625%
Discount rate			18.00%		18.00%
Recovery period			4 years 4 months 24 days		4 years 9 months 18 days
Minimum
Servicing Liabilities at Fair Value [Line Items]
Recovery period			3 years 9 months 18 days		4 years 7 months 6 days
Maximum
Servicing Liabilities at Fair Value [Line Items]
Recovery period			4 years 10 months 24 days		4 years 10 months 24 days

Loan Receivables Held for Sal_2

Loan Receivables Held for Sale - Activity in the balance of loan receivables held for sale (Details) - USD ($) $ in Thousands	Sep. 27, 2018	Jun. 27, 2018	May 21, 2018	Jun. 29, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow
Beginning balance							$ 73,606	$ 41,268
Additions							70,805	104,573
Proceeds from sales and customer payments							(126,981)	(33,554)
Gain/(loss) on sold loan receivables held for sale							0	(88)
Decrease/(increase) in valuation allowance							(110)	0
Transfers							22	(4,956)
Write offs and other							(2,577)	(2,393)
Ending balance					$ 14,765	$ 104,850	14,765	104,850
Sales of loans	$ 48,176	$ 50,614	$ 9,552	$ 17,900		0	108,342	17,900
Recovery payments received					9	29	42	218
Proceeds					9,152	6,000	19,323	6,000
Loan receivables held for sale
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow
Proceeds					$ 113	$ 86	$ 284	$ 86

Loan Receivables Held for Sal_3

Loan Receivables Held for Sale - Activities associated with loan receivable sales and servicing activities (Details) - USD ($) $ in Thousands	Sep. 27, 2018	Jun. 27, 2018	May 21, 2018	Jun. 29, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Receivables [Abstract]
Gain/(loss) on sold loan receivables held for sale					$ 0	$ 0	$ 0	$ (88)
Cash Flows
Sales of loans	$ 48,176	$ 50,614	$ 9,552	$ 17,900		0	108,342	17,900
Servicing fees					$ 546	$ 550	$ 1,645	$ 2,261

Loan Receivables Held for Sal_4

Loan Receivables Held for Sale - Principal balances of sold loan receivables (Details) - Bank Partners - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Total principal balance	$ 350,296		$ 350,296		$ 305,748
Delinquent loans (unpaid principal balance)	24,841		24,841		$ 20,409
Net charge-offs (unpaid principal balance)	$ 2,017	$ 2,265	$ 6,729	$ 5,270

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	$ 18,992	$ 18,634
Allowance for Losses	(369)	(276)
Accounts receivable, net	18,623	18,358
Transaction related
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	17,605	15,997
Allowance for Losses	(369)	(276)
Accounts receivable, net	17,236	15,721
Servicing related
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Gross	1,387	2,637
Allowance for Losses	0	0
Accounts receivable, net	$ 1,387	$ 2,637

Property, Equipment and Softw_3

Property, Equipment and Software (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Software, Gross	$ 7,244	$ 4,836
Property, Plant and Equipment, Software Gross	17,183	14,186
Less: accumulated depreciation	(5,162)	(4,060)
Less: accumulated amortization	(2,253)	(2,278)
Total property, equipment and software, net	9,768	7,848
Furniture
Property, Plant and Equipment [Line Items]
Total property, equipment and software, at cost	2,813	2,704
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, equipment and software, at cost	4,114	3,659
Computer hardware
Property, Plant and Equipment [Line Items]
Total property, equipment and software, at cost	$ 3,012	$ 2,987

Borrowings - Credit Agreement (

Borrowings - Credit Agreement (Details) - USD ($)	May 23, 2018	Mar. 31, 2018	Aug. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Mar. 29, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Original issuance discount				$ 3,882,000		$ 3,882,000	$ 3,882,000			$ 3,321,000
Debt issuance costs				6,717,000		6,717,000	6,717,000			7,541,000
Credit Agreement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 450,000,000
First lien net leverage ratio for any measurement date at which the principal amounts of outstanding revolving loans and letters of credit exceed 25% of the aggregate principal amount of the revolving loan facility			3.50
Maximum first lien net leverage ratio to make distributions			3
Term loan
Debt Instrument [Line Items]
Subsequent payments to certain equity holders and a related party	$ 48,800,000						46,900,000
Term loan | Other Liabilities
Debt Instrument [Line Items]
Reserved payment liability				1,800,000		1,800,000	1,800,000
Term loan | Related Party Liabilities
Debt Instrument [Line Items]
Reserved payment liability				100,000		100,000	100,000
Term loan | Original term loan
Debt Instrument [Line Items]
Debt instrument, face amount			$ 350,000,000
Original issuance discount			3,500,000
Debt issuance costs			7,949,000
Proceeds from the term loan			338,600,000
Cash reserved for repayment to equity holders and related party			7,900,000
Cash and debt reserved for repayment to equity holders and related part			$ 346,500,000
Subsequent payments to certain equity holders and a related party							340,700,000
Repayments of Debt		$ 349,100,000
Term loan | Original term loan | Other Liabilities
Debt Instrument [Line Items]
Reserved payment liability				5,800,000		5,800,000	5,800,000
Term loan | Original term loan | LIBOR
Debt Instrument [Line Items]
Margin (as a percent)			4.00%
Term loan | Modified term loan
Debt Instrument [Line Items]
Debt instrument, face amount		400,000,000
Proceeds from the term loan		399,000,000
Payments of financing costs		1,100,000
Unamortized discount		$ 1,000,000
Term loan | Modified term loan | LIBOR
Debt Instrument [Line Items]
Margin (as a percent)		3.25%
Revolving credit facility | Original revolving credit facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 100,000,000
Borrowings under the revolving loan facility				0		0	0			0
Threshold first lien net leverage ratio			1.50
Line of Credit Facility, Unused Fee				96,000	$ 49,000		317,000	$ 49,000
Reduced interest margin (percent)			0.375%
Per annum commitment fee (percent)			0.50%
Revolving credit facility | Original revolving credit facility | Federal funds rate
Debt Instrument [Line Items]
Margin (as a percent)			0.50%
Revolving credit facility | Original revolving credit facility | LIBOR
Debt Instrument [Line Items]
Margin (as a percent)			1.00%
Revolving credit facility | Original revolving credit facility | One-Month LIBOR plus 1%
Debt Instrument [Line Items]
Margin (as a percent)			3.00%
Revolving credit facility | Original revolving credit facility | LIBOR adjusted
Debt Instrument [Line Items]
Margin (as a percent)			4.00%
Revolving credit facility | Original revolving credit facility | Base rate loans
Debt Instrument [Line Items]
Reduced interest margin (percent)			2.75%
Revolving credit facility | Original revolving credit facility | Eurodollar loans
Debt Instrument [Line Items]
Reduced interest margin (percent)			3.75%
Revolving credit facility | Modified revolving credit facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity									$ 100,000,000
Borrowings under the revolving loan facility				0		$ 0	0
Threshold first lien net leverage ratio						1.50
Revolving credit facility | Modified revolving credit facility | LIBOR
Debt Instrument [Line Items]
Margin (as a percent)						3.00%
Reduced interest margin (percent)						3.25%
Revolving credit facility | Modified revolving credit facility | Base rate loans
Debt Instrument [Line Items]
Margin (as a percent)						2.00%
Reduced interest margin (percent)						2.25%
Letter of credit | Original revolving credit facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				$ 10,000,000		$ 10,000,000	$ 10,000,000			$ 0
Letter of credit | Modified revolving credit facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity									$ 10,000,000

Borrowings - Schedule of term l

Borrowings - Schedule of term loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Aug. 31, 2017
Debt Instrument [Line Items]
Term loan, face value	$ 398,000		$ 398,000		$ 349,125
Unamortized debt discount	(3,882)		(3,882)		(3,321)
Unamortized debt issuance costs	(6,717)		(6,717)		(7,541)
Term loan	387,401		387,401		$ 338,263
Amortization of debt issuance costs			1,262	$ 270
Term loan
Debt Instrument [Line Items]
Amortization of debt discount	155	$ 52	438	52
Amortization of debt issuance costs	267	$ 119	$ 824	$ 119
Term loan | Original term loan
Debt Instrument [Line Items]
Unamortized debt discount						$ (3,500)
Unamortized debt issuance costs						$ (7,949)
Quarterly amortization rate			0.25%
Term loan | Modified term loan
Debt Instrument [Line Items]
Quarterly amortization rate			0.25%
Principal repayments expected to be made in the next year	4,000		$ 4,000
Principal repayments expected to be made in year two	4,000		4,000
Principal repayments expected to be made in year three	4,000		4,000
Principal repayments expected to be made in year four	4,000		4,000
Principal repayments expected to be made in year five	$ 4,000		$ 4,000

Borrowings - Credit Facility (N

Borrowings - Credit Facility (Narrative) (Details) - USD ($)	Feb. 10, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Line of Credit Facility [Line Items]
Loss on extinguishment of debt		$ 254,000	$ 0	$ 254,000
Revolving credit facility | Initial Credit Facility
Line of Credit Facility [Line Items]
Term of credit facility	2 years
Line of credit facility, maximum borrowing capacity	$ 50,000,000
Maximum borrowing capacity upon request and successful syndication	$ 100,000,000
Borrowings under the credit facility					$ 0
Commitment fees within interest expense		61,000		159,000
Amortization of fees		$ 24,000		$ 99,000

Other Liabilities (Details)

Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Deferred lease liabilities	$ 2,618		$ 2,819
Transaction processing liabilities	18,741		16,435
Servicing liabilities	2,692	$ 2,272	2,071	$ 800	$ 0	$ 0
Distributions payable	10,565		13,189
Accruals and other liabilities	5,033		4,327
Total other liabilities	$ 39,649		$ 38,841

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) - shares	Sep. 30, 2018	Dec. 31, 2017
Class A common stock
Noncontrolling Interest [Line Items]
Common stock, outstanding (in shares)	57,797,385	0
GS Holdings
Noncontrolling Interest [Line Items]
Economic interest (as a percent)	31.30%

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	May 24, 2018$ / sharesshares	May 23, 2018	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense | $			$ 4,304	$ 3,032
Compensation not yet recognized, stock options, nonvested awards | $			$ 9,700
Award requisite service period (in years)			4 years 1 month 10 days
Stock split, conversion ratio		10
Unvested HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award requisite service period (in years)			3 years 9 months 18 days
Compensation not yet recognized, nonvested awards | $			$ 14,400
Unvested Class A stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award requisite service period (in years)			4 years 7 days
Compensation not yet recognized, nonvested awards | $			$ 4,100
Profits Interests converted into vested and unvested HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares converted as part of the Reorganization Transaction (in shares)	15,241,530
Price per share (in dollars per share) | $ / shares	$ 23
Profits Interests converted into vested and unvested HoldCo Units | Vested HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new shares converted from Profit Interests (in shares)	2,941,139
Profits Interests converted into vested and unvested HoldCo Units | Unvested HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new shares converted from Profit Interests (in shares)	3,172,843
Profits Interests converted into vested and unvested Class A stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares converted as part of the Reorganization Transaction (in shares)	940,000
Price per share (in dollars per share) | $ / shares	$ 23
Profits Interests converted into vested and unvested Class A stock awards | Vested Class A stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new shares converted from Profit Interests (in shares)	127,327
Profits Interests converted into vested and unvested Class A stock awards | Unvested Class A stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of new shares converted from Profit Interests (in shares)	255,904
Class A common stock | 2018 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	24,000,000

Share-Based Compensation - Clas

Share-Based Compensation - Class A Common Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	May 24, 2018	Sep. 30, 2018	May 23, 2018	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercises in period, intrinsic value					$ 396
Shares exercised by means of cashless net exercise procedure (in shares)				252,000
Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)			9,821,884	9,821,884	10,006,890
Granted (in shares)		1,014,029	340,000		450,000
Exercised (in shares)		(42,000)	(270,000)		(202,000)
Forfeited (in shares)		(202,000)	(260,000)		(400,500)
Effect of Reorganization Transactions and IPO (in shares)	(186,772)
Outstanding at end of period (in shares)		10,215,141		10,215,141	9,854,390
Exercisable at end of period (in shares)		7,237,582		7,237,582	6,718,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at beginning of period (in dollars per share)			$ 2.65	$ 2.65
Granted (in dollars per share)		$ 21.72	14.95
Exercised (in dollars per share)		1.39	3.19
Forfeited (in dollars per share)		19.34	$ 6.41
Effect of Reorganization Transactions and IPO (in dollars per share)	$ 7.56
Outstanding at end of period (in dollars per share)		4.43		4.43
Exercisable at end of period (in dollars per share)		$ 1.54		1.54
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average grant date fair value, grants in period (in dollars per share)				$ 6.29	$ 3.42
Exercises in period, intrinsic value				$ 1,475
Issuance of shares by means of cashless net exercise procedure (in shares)				9,964
Employees
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Proceeds from issuance of shares under share-based compensation plans				$ 339
HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Issuance of shares by means of cashless net exercise procedure (in shares)				38,637
HoldCo Units | Employees
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised (in shares)				(30,516)

Share-Based Compensation - Intr

Share-Based Compensation - Intrinsic Value (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, outstanding, intrinsic value	$ 56.1
Options, exercisable, intrinsic value	$ 45.7
Options, outstanding, weighted average remaining contractual term	5 years 5 months 1 day
Options, exercisable, weighted average remaining contractual term	4 years 4 months 28 days

Share-Based Compensation - Prof

Share-Based Compensation - Profits Interests (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in period, fair value	$ 371	$ 1,204
Profit Interests
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Outstanding at beginning of period (in shares)	14,061,530	12,616,890
Granted (in shares)	2,920,000	420,000
Forfeited (in shares)	(800,000)	(880,000)
Redeemed (in shares)	0	0
Effect of Reorganization Transactions and IPO (in shares)	(16,181,530)
Outstanding at beginning of period (in shares)	0	12,156,890
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of period (in dollars per share)	$ 8.23
Granted (in dollars per share)	14.31
Forfeited (in dollars per share)	9.32
Effect of Reorganization Transactions and IPO (in dollars per share)	9.27
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Grants in period, weighted average grant date fair value (in dollars per share)	$ 4.47	$ 2.71

Share-Based Compensation - Unve

Share-Based Compensation - Unvested HoldCo Units, Class A Common Stock Awards, and RSAs (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)$ / sharesshares
Unvested HoldCo Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at beginning of period (in shares)	0
Effect of Reorganization Transactions and IPO (in shares)	3,172,843
Granted (in shares)	0
Forfeited (in shares)	(156,739.13)
Vested (in shares)	(118,082)
Unvested at June 30, 2018 (in shares)	2,898,022
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Effect of Reorganization Transactions and IPO (in dollars per share) | $ / shares	$ 23
Forfeited (in dollars per share) | $ / shares	23
Vested (in dollars per share) | $ / shares	23
Unvested at June 30, 2018 (in dollars per share) | $ / shares	$ 23
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in period, fair value | $	$ 2,716
Unvested Class A stock awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested at beginning of period (in shares)	0
Effect of Reorganization Transactions and IPO (in shares)	255,904
Granted (in shares)	137,170
Forfeited (in shares)	0
Vested (in shares)	(15,049)
Unvested at June 30, 2018 (in shares)	378,025
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Effect of Reorganization Transactions and IPO (in dollars per share) | $ / shares	$ 23
Granted (in dollars per share) | $ / shares	19.71
Vested (in dollars per share) | $ / shares	23
Unvested at June 30, 2018 (in dollars per share) | $ / shares	$ 21.81
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested in period, fair value | $	$ 346

Taxation (Details)

Taxation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 24, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate (as a percent)	6.90%		4.50%
Income tax expense	$ 3,375	$ 0	$ 4,969	$ 0
Federal and state statutory rate			23.50%
Deferred tax assets, net	297,983		$ 297,983		$ 245,836	$ 0
Deferred income tax assets, related to TRA	57,116		57,116
Tax receivable agreement liability	$ 255,823		$ 255,823			$ 0

Commitments, Contingencies an_3

Commitments, Contingencies and Guarantees - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Number of consecutive periods	5		5
Renewal term (in years)	3 years		3 years
Rent expense	$ 810	$ 759	$ 2,366	$ 2,234
Unused commitments to extend credit	3,800		3,800
Restricted cash	160,909	$ 120,289	160,909	$ 120,289	$ 129,224
Collectibility of Receivables
Loss Contingencies [Line Items]
Loss contingency accrual	2,700		2,700
GreenSky, LLC
Loss Contingencies [Line Items]
Tangible capital	7,500		7,500
Minimum aggregate net income, four fiscal quarters			$ 5,000
Maximum ratio of liabilities to equity			3
Financial Guarantee
Loss Contingencies [Line Items]
Restricted cash	91,200		$ 91,200
Guarantees, fair value	500		500
Contractual Restricted Cash Under Arrangement
Loss Contingencies [Line Items]
Restricted cash	44,700		44,700
Bank Partners
Loss Contingencies [Line Items]
Financing receivable, nonaccrual status	$ 15,700		$ 15,700

Commitments, Contingencies an_4

Commitments, Contingencies and Guarantees - Future Minimum Lease Payments (Details) $ in Thousands	Sep. 30, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2018	$ 907
2,019	3,725
2,020	3,815
2,021	3,878
2,022	2,827
2023 and thereafter	1,647
Total minimum lease payments	$ 16,799

Related Party Transactions - Na

Related Party Transactions - Narrative (Details)	1 Months Ended			3 Months Ended		9 Months Ended
	May 31, 2018USD ($)	Aug. 31, 2017USD ($)	Nov. 30, 2016USD ($)director	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Related Party Transaction [Line Items]
Related party liabilities				$ 937,000		$ 937,000		$ 1,548,000
Payments of distributions						141,019,000	$ 405,653,000
Distributions accrued but not paid				10,887,000	$ 9,508,000	10,887,000	9,508,000
Related party receivables				122,000		122,000		218,000
Special operating distribution
Related Party Transaction [Line Items]
Distributions	$ 26,200,000
Payments of distributions						25,100,000
Distributions accrued but not paid				900,000		900,000
Affiliated Entity | Special operating distribution
Related Party Transaction [Line Items]
Related party liabilities				200,000		200,000
Payments of distributions						1,000,000
Rent expense | Common Management
Related Party Transaction [Line Items]
Related party expenses				439,000	373,000	1,252,000	1,118,000
Recruiting Services | Director
Related Party Transaction [Line Items]
Related party expenses				375,000		375,000
Related party liabilities				61,000		61,000
Loans receivable | Non-Executive Employees
Related Party Transaction [Line Items]
Related party receivables				122,000		122,000		210,000
Share-based compensation | Affiliated Entity
Related Party Transaction [Line Items]
Related party expenses				0	95,000	0	285,000
Bank partner agreement | Financing Partner
Related Party Transaction [Line Items]
Related party expenses				0	$ 0	0	$ 69,000
Related party liabilities				0		0		445,000
Related party transaction amount			$ 20,000,000
Number of directors | director			2
Related party receivables				0		0		8,000
Committed balance by related party				0		0		$ 11,700,000
Term loan transaction | Affiliated Entity
Related Party Transaction [Line Items]
Related party expenses		$ 2,600,000
Related party liabilities				$ 500,000		$ 500,000

Related Party Transactions - Sc

Related Party Transactions - Schedule of Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Related Party Transaction [Line Items]
Related party receivables	$ 122		$ 122		$ 218
Related party liabilities	937		937		1,548
Bank partner agreement | Financing Partner
Related Party Transaction [Line Items]
Related party receivables	0		0		8
Related party liabilities	0		0		445
Restricted cash	0		0		$ 437
Servicing and other	0	$ 32	54	$ 248
Related party expenses	$ 0	$ 0	$ 0	$ 69

Segment Reporting (Details)

Segment Reporting (Details)	9 Months Ended
	Sep. 30, 2018segment
Segment Reporting [Abstract]
Number of reportable segments	1

Variable Interest Entities (Det

Variable Interest Entities (Details)	9 Months Ended
	Sep. 30, 2018
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
VIE, ownership percentage	100.00%

Variable Interest Entities - Ba

Variable Interest Entities - Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash	$ 294,336	$ 224,614	$ 105,293
Restricted cash	160,909	129,224	120,289
Loan receivables held for sale, net	14,765	73,606	$ 104,850	$ 41,268
Accounts receivable, net	18,623	18,358
Related party receivables	122	218
Property, equipment and software, net	9,768	7,848
Other assets	4,989	9,021
Total assets	801,495	462,889
Liabilities
Accounts payable	6,134	6,845
Accrued compensation and benefits	5,525	7,677
Other accrued expenses	1,013	1,606
Finance charge reversal liability	117,202	94,148
Term loan	387,401	338,263
Related party liabilities	937	1,548
Other liabilities	39,649	38,841
Total liabilities	813,684	488,928
Permanent Equity (Deficit)
Total permanent equity (deficit)	(12,189)
Total liabilities, temporary and permanent equity (deficit)	801,495	$ 462,889
Variable Interest Entity, Primary Beneficiary
Assets
Cash	285,310
Restricted cash	160,909
Loan receivables held for sale, net	14,765
Accounts receivable, net	18,623
Related party receivables	122
Property, equipment and software, net	9,768
Other assets	4,989
Total assets	494,486
Liabilities
Accounts payable	6,134
Accrued compensation and benefits	5,525
Other accrued expenses	1,013
Finance charge reversal liability	117,202
Term loan	387,401
Related party liabilities	937
Other liabilities	39,649
Total liabilities	557,861
Permanent Equity (Deficit)
Noncontrolling interest	(41,533)
Total permanent equity (deficit)	(21,842)
Total permanent equity (deficit)	(63,375)
Total liabilities, temporary and permanent equity (deficit)	$ 494,486

Variable Interest Entities - St

Variable Interest Entities - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Variable Interest Entity [Line Items]
Total revenue	$ 113,912	$ 88,316	$ 304,942	$ 236,073
Total operating expenses	59,655	48,224	180,300	137,050
Operating profit	54,257	40,092	124,642	99,023
Total other income/(expense), net	(5,170)	(1,930)	(14,541)	(257)
Income before income tax expense	49,087	$ 38,162	110,101	$ 98,766
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Total revenue	113,912		304,942
Total operating expenses	59,655		180,300
Operating profit	54,257		124,642
Total other income/(expense), net	(5,170)		(14,541)
Income before income tax expense	$ 49,087		$ 110,101

Variable Interest Entities - _2

Variable Interest Entities - Statement of Cash Flow (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net cash provided by operating activities	$ 203,421	$ 67,585
Net cash used in investing activities	(4,849)	(2,575)
Net cash used in financing activities	(97,165)	(67,542)
Net increase/(decrease) in cash and restricted cash	101,407	(2,532)
Cash and restricted cash at beginning of period	353,838	228,114
Cash and restricted cash at end of period	455,245	$ 225,582
Variable Interest Entity, Primary Beneficiary
Cash flows from operating activities
Net cash provided by operating activities	203,421
Net cash used in investing activities	(4,849)
Net cash used in financing activities	(106,191)
Net increase/(decrease) in cash and restricted cash	92,381
Cash and restricted cash at beginning of period	353,838
Cash and restricted cash at end of period	$ 446,219

Temporary Equity (Details)

Temporary Equity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Temporary Equity [Line Items]
Temporary equity, carrying amount	$ 0	$ 430,348	$ 272,367	$ 335,720
Preferred Class B
Temporary Equity [Line Items]
Temporary equity, aggregate redemption amount		215,800
Preferred Class C-1
Temporary Equity [Line Items]
Temporary equity, aggregate redemption amount		191,400
Preferred Class C-2
Temporary Equity [Line Items]
Temporary equity, aggregate redemption amount		$ 43,000

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) - USD ($) $ in Millions	Oct. 24, 2018	Sep. 30, 2018
Subsequent Event [Line Items]
Unused commitments to extend credit		$ 3.8
Subsequent Event
Subsequent Event [Line Items]
Payments to purchase loans held-for-sale	$ 20.1
Unfunded Loan Commitment | Subsequent Event
Subsequent Event [Line Items]
Unused commitments to extend credit	$ 11.2

Uncategorized Items - gsky-2018

Label	Element	Value
Temporary Equity, Elimination as Part of Reorganization	us-gaap_TemporaryEquityEliminationAsPartofReorganization	$ 413,990,000
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	496,000
Adjustment To Additional Paid In Capital, Deferred Tax Adjustment Related To Tax Receivable Agreement	gsky_AdjustmentToAdditionalPaidInCapitalDeferredTaxAdjustmentRelatedToTaxReceivableAgreement	47,129,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	511,176,000
Limited Liability Company (LLC) Members' Equity, Unit-based Compensation	us-gaap_LimitedLiabilityCompanyLLCMembersEquityUnitBasedCompensation	2,132,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	0
Purchases Of Subsidiary Units In Connection With IPO	gsky_PurchasesOfSubsidiaryUnitsInConnectionWithIPO	901,833,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	27,376,000
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2,172,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared, Including Temporary Equity	gsky_DistributionMadetoLimitedLiabilityCompanyLLCMemberCashDistributionsDeclaredIncludingTemporaryEquity	111,341,000
Temporary Equity, Distributions	gsky_TemporaryEquityDistributions	16,358,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	339,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	94,983,000
Noncontrolling Interest [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	49,368,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	5,433,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	27,035,000
Noncontrolling Interest, Effect Of Reorganization	gsky_NoncontrollingInterestEffectOfReorganization	(69,299,000)
Additional Paid-in Capital [Member]
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	496,000
Adjustment To Additional Paid In Capital, Deferred Tax Adjustment Related To Tax Receivable Agreement	gsky_AdjustmentToAdditionalPaidInCapitalDeferredTaxAdjustmentRelatedToTaxReceivableAgreement	47,129,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	590,905,000
Limited Liability Company (LLC) Members' Equity, Unit-based Compensation	us-gaap_LimitedLiabilityCompanyLLCMembersEquityUnitBasedCompensation	2,132,000
Noncontrolling Interest, Increase From Vesting Of Shares	gsky_NoncontrollingInterestIncreaseFromVestingOfShares	(5,433,000)
Purchases Of Subsidiary Units In Connection With IPO	gsky_PurchasesOfSubsidiaryUnitsInConnectionWithIPO	901,833,000
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Equity-Based Payments To Non-Employees	gsky_EquityBasedPaymentsToNonEmployees	(6,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2,172,000
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	339,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	37,980,000
Noncontrolling Interest, Effect Of Reorganization	gsky_NoncontrollingInterestEffectOfReorganization	69,299,000
Retained Earnings [Member]
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	17,551,000
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	(79,729,000)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	341,000
Distribution Made to Limited Liability Company (LLC) Member, Cash Distributions Declared	us-gaap_DistributionMadeToLimitedLiabilityCompanyLLCMemberCashDistributionsDeclared	57,003,000
Additional Paid In Capital - LLC [Member]
Stock Issued During Period, Value, Conversion of Units	us-gaap_StockIssuedDuringPeriodValueConversionOfUnits	(97,344,000)
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, Shares, Share-based Compensation, Forfeited	us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited	(156,739)
Stock Issued During Period, Value, New Issues	us-gaap_StockIssuedDuringPeriodValueNewIssues	$ 129,000
Common Class A [Member]
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	0
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(127,000)
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	53,012,000
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] | Common Stock [Member]
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	1,000
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, Shares, Conversion of Units	us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits	15,816,268
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	137,170
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised	125,398
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised	9,964
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 A [Member] | Additional Paid-in Capital [Member]
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(1,000)
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(127,000)
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	52,988,000
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)