Line of Credit Facility, Maximum Borrowing Capacity, Increase

No definition available.

Name:	ondk_LineofCreditFacilityMaximumBorrowingCapacityIncrease
Namespace Prefix:	ondk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Period Type:	duration

- Details

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- Details

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Balance Type:
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- Details

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- Details

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Namespace Prefix:
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- Details

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- Details

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Subsequent Events (Details) - Revolving Credit Facility - USD ($)	Feb. 08, 2019	Jan. 31, 2019	Jan. 28, 2019	Jun. 17, 2016	Mar. 20, 2017	Jun. 16, 2016
Debt Facility, Sun Trust Facility Agreement, Due January 2021 \| Subsequent Event
Subsequent Event [Line Items]
Revolving debt commitment amount		$ 85,000,000	$ 85,000,000
Debt Facility, Loan Assets of OnDeck, LLC, Due April 2022 \| Subsequent Event
Subsequent Event [Line Items]
Variable interest spread	0.25%
Increase in line of credit	$ 50,000,000
Credit Facility Due March 2019
Subsequent Event [Line Items]
Revolving debt commitment amount				$ 162,400,000.0	$ 214,100,000	$ 150,000,000
Increase in line of credit				$ 12,400,000
LIBOR \| Debt Facility, Sun Trust Facility Agreement, Due January 2021 \| Subsequent Event
Subsequent Event [Line Items]
Variable interest spread		3.00%	3.00%
LIBOR \| Credit Facility Due March 2019
Subsequent Event [Line Items]
Variable interest spread				8.00%