Debt Instrument, Basis Spread on Variable Rate, One Month Interest Period

No definition available.

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- Definition

Debt Instrument, Basis Spread on Variable Rate, Per Annum

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The interest rate spread added to applicable interest rate of term loans in the case of default by entity.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

LIBOR Maturity Period

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of loam amortization in year five.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Percentage of loam amortization in year four.

+ References

No definition available.

+ Details

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

- Definition

Percentage of loan amortization in year one.

+ References

No definition available.

+ Details

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

- Definition

Percentage of loam amortization in year three.

+ References

No definition available.

+ Details

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Namespace Prefix:	csgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of loam amortization in year two.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

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

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Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discussion of whether the borrowings under the credit facility are secured or unsecured and, if secured, a description of collateral (for example, accounts receivable less than 120 days old, finished goods inventory).

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+ Details

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- Definition

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

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Period Type:	duration

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- Details

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LONG-TERM DEBT (Details) - USD ($)		1 Months Ended	9 Months Ended
LONG-TERM DEBT (Details) - USD ($)	Apr. 02, 2014	Jun. 30, 2014	Sep. 30, 2016	Dec. 31, 2015	Apr. 01, 2014
Debt Instrument [Line Items]
Line of credit facility, amount outstanding					$ 150,000,000
Repayments of revolving credit facility		$ 150,000,000
Repayments of term loan	$ 149,000,000
LIBOR maturity period (in months)	1 month
Default interest rate per annum on overdue amounts (in percent)					2.00%
Credit facility, collateral			The obligations under the 2014 Credit Agreement are guaranteed by all material subsidiaries of the Company and are secured by a lien on substantially all of the assets of the Company and those of its material subsidiaries, in each case subject to certain exceptions, pursuant to security and guarantee documents entered into on the Closing Date.
Capitalized debt issuance costs					$ 10,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding			$ 0	$ 0
CoStar Group [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument borrowing capacity					400,000,000
Term of loan (in years)	5 years
CoStar Group [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument borrowing capacity					225,000,000
Term of loan (in years)	5 years
CoStar Group [Member] \| Swingline Loan [Member]
Debt Instrument [Line Items]
Revolving credit sub-facility for swing-line loans and issuances of letters of credit					10,000,000
CoStar Group [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Revolving credit sub-facility for swing-line loans and issuances of letters of credit					$ 10,000,000
CoStar Group [Member] \| Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Annual amortization, first year after closing (in percent)					5.00%
Annual amortization, second year after closing (in percent)					5.00%
Annual amortization, third year after closing (in percent)					5.00%
Annual amortization, fourth year after closing (in percent)					10.00%
Annual amortization, fifth year after closing (in percent)					15.00%
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Basis spread on federal funds rate (in percent)	0.50%
LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on federal funds rate (in percent)	2.00%
Debt instrument, basis spread on variable rate, one month interest period (in percent)					1.00%
Debt instrument, basis spread on variable rate, per annum (in percent)					1.00%