| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | COSTAR GROUP, INC. |
| Entity Central Index Key | 0001057352 |
| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | Pay Versus Performance As required by Section 953(a) of the Dodd-Frank Act, we are providing the information below to illustrate the relationship between the SEC-defined S-K. S-K 3 The following table sets forth information concerning the compensation of our NEOs and our financial performance for each of the three years in the period ended December 31, 2022: YEAR SUMMARY ($) COMPENSATION (1) ($) AVERAGE NON-PEO AVERAGE NON-PEO (1) NEOS ($) VALUE OF INITIAL FIXED $100 NET ($ IN 000S) ADJUSTED (3) ($ IN 000S) TOTAL ($) PEER GROUP (2) ($) 2022 $ 19,420,514 $ 16,180,113 $ 5,633,566 $ 4,583,956 $ 129.17 $ 102.47 $ 369,453 $ 671,511 2021 $ 22,164,341 $ 11,430,937 $ 6,616,193 $ 3,506,869 $ 132.09 $ 133.08 $ 292,564 $ 647,408 2020 $ 21,304,754 $ 43,421,540 $ 5,349,361 $ 2,432,888 $ 154.48 $ 116.09 $ 227,128 $ 553,186 (1) The amounts shown represent “compensation actually paid” (“CAP”) to our PEO and the average CAP to our remaining NEOs for the relevant fiscal year, as determined under SEC rules (and described below), which includes the individuals indicated in the table below for each fiscal year: YEAR PEO NON-PEO 2022 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles, Frederick G. Saint and Frank A. Simuro 2021 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles and Frederick G. Saint 2020 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles, Frederick G. Saint and Matthew F.W. Linnington CAP to our NEOs represents the “Total” compensation reported in the Summary Compensation Table for the applicable fiscal year, as adjusted as follows: ADJUSTMENTS 2022 2021 2020 PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO Deduction for Amounts Reported under the “Stock Awards” and “Option Awards” Columns in the 2022 Summary Compensation Table for Applicable Year -$15,526,424 -$4,293,321 -$18,710,768 -$5,277,307 -$18,492,242 -$4,670,083 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Remain Unvested as of Applicable Year End, determined as of Applicable Year End $18,416,210 $4,567,643 $14,435,844 $3,840,076 $20,330,911 $3,667,266 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Vested during Applicable Year, determined as of Vesting Date $ 3,551 $ 0 $ 0 $ 301 $ 0 $ 530 Increase/deduction for Awards Granted during Prior Year(s) that were Outstanding and Unvested as of Applicable Year End, determined based on change in ASC 718 Fair Value from Prior Year End to Applicable Year End $ 756,384 $ 183,671 -$ 3,584,582 -$ 849,736 $18,080,010 $3,382,952 Increase/deduction for Awards Granted during Prior Year(s) that Vested During Applicable Year, determined based on change in ASC 718 Fair Value from Prior Year End to Vesting Date -$ 6,890,122 -$1,507,603 -$ 2,873,898 -$ 822,658 $ 2,198,107 $ 573,190 Deduction of ASC 718 Fair Value of Awards Granted during Prior Year(s) that were Forfeited during Applicable Year, determined as of Prior Year End $ 0 $ 0 $ 0 $ 0 $ 0 -$5,870,328 Total Adjustments -$ 3,240,401 -$1,049,610 -$10,733,404 -$3,109,324 $22,116,786 -$2,916,473 (2) Pursuant to SEC rules, the TSR amounts assume an initial investment of $100 on December 31, 2019. As permitted by SEC rules, the peer group referenced for purposes of the TSR comparison is the group of companies included in the S&P 500 Internet Services & Infrastructure Index, which is the industry peer group used for purposes of Item 201(e) of Regulation S-K. (3) Adjusted EBITDA non-GAAP | ||
| Company Selected Measure Name | Adjusted EBITDA | ||
| Named Executive Officers, Footnote [Text Block] | (1) The amounts shown represent “compensation actually paid” (“CAP”) to our PEO and the average CAP to our remaining NEOs for the relevant fiscal year, as determined under SEC rules (and described below), which includes the individuals indicated in the table below for each fiscal year: YEAR PEO NON-PEO 2022 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles, Frederick G. Saint and Frank A. Simuro 2021 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles and Frederick G. Saint 2020 Andrew C. Florance Scott T. Wheeler, Lisa C. Ruggles, Frederick G. Saint and Matthew F.W. Linnington | ||
| Peer Group Issuers, Footnote [Text Block] | Pursuant to SEC rules, the TSR amounts assume an initial investment of $100 on December 31, 2019. As permitted by SEC rules, the peer group referenced for purposes of the TSR comparison is the group of companies included in the S&P 500 Internet Services & Infrastructure Index, which is the industry peer group used for purposes of Item 201(e) of Regulation S-K. | ||
| PEO Total Compensation Amount | $ 19,420,514 | $ 22,164,341 | $ 21,304,754 |
| PEO Actually Paid Compensation Amount | $ 16,180,113 | 11,430,937 | 43,421,540 |
| Adjustment To PEO Compensation, Footnote [Text Block] | ADJUSTMENTS 2022 2021 2020 PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO Deduction for Amounts Reported under the “Stock Awards” and “Option Awards” Columns in the 2022 Summary Compensation Table for Applicable Year -$15,526,424 -$4,293,321 -$18,710,768 -$5,277,307 -$18,492,242 -$4,670,083 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Remain Unvested as of Applicable Year End, determined as of Applicable Year End $18,416,210 $4,567,643 $14,435,844 $3,840,076 $20,330,911 $3,667,266 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Vested during Applicable Year, determined as of Vesting Date $ 3,551 $ 0 $ 0 $ 301 $ 0 $ 530 Increase/deduction for Awards Granted during Prior Year(s) that were Outstanding and Unvested as of Applicable Year End, determined based on change in ASC 718 Fair Value from Prior Year End to Applicable Year End $ 756,384 $ 183,671 -$ 3,584,582 -$ 849,736 $18,080,010 $3,382,952 Increase/deduction for Awards Granted during Prior Year(s) that Vested During Applicable Year, determined based on change in ASC 718 Fair Value from Prior Year End to Vesting Date -$ 6,890,122 -$1,507,603 -$ 2,873,898 -$ 822,658 $ 2,198,107 $ 573,190 Deduction of ASC 718 Fair Value of Awards Granted during Prior Year(s) that were Forfeited during Applicable Year, determined as of Prior Year End $ 0 $ 0 $ 0 $ 0 $ 0 -$5,870,328 Total Adjustments -$ 3,240,401 -$1,049,610 -$10,733,404 -$3,109,324 $22,116,786 -$2,916,473 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 5,633,566 | 6,616,193 | 5,349,361 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 4,583,956 | 3,506,869 | 2,432,888 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | ADJUSTMENTS 2022 2021 2020 PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO PEO AVERAGE NON-PEO Deduction for Amounts Reported under the “Stock Awards” and “Option Awards” Columns in the 2022 Summary Compensation Table for Applicable Year -$15,526,424 -$4,293,321 -$18,710,768 -$5,277,307 -$18,492,242 -$4,670,083 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Remain Unvested as of Applicable Year End, determined as of Applicable Year End $18,416,210 $4,567,643 $14,435,844 $3,840,076 $20,330,911 $3,667,266 Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Vested during Applicable Year, determined as of Vesting Date $ 3,551 $ 0 $ 0 $ 301 $ 0 $ 530 Increase/deduction for Awards Granted during Prior Year(s) that were Outstanding and Unvested as of Applicable Year End, determined based on change in ASC 718 Fair Value from Prior Year End to Applicable Year End $ 756,384 $ 183,671 -$ 3,584,582 -$ 849,736 $18,080,010 $3,382,952 Increase/deduction for Awards Granted during Prior Year(s) that Vested During Applicable Year, determined based on change in ASC 718 Fair Value from Prior Year End to Vesting Date -$ 6,890,122 -$1,507,603 -$ 2,873,898 -$ 822,658 $ 2,198,107 $ 573,190 Deduction of ASC 718 Fair Value of Awards Granted during Prior Year(s) that were Forfeited during Applicable Year, determined as of Prior Year End $ 0 $ 0 $ 0 $ 0 $ 0 -$5,870,328 Total Adjustments -$ 3,240,401 -$1,049,610 -$10,733,404 -$3,109,324 $22,116,786 -$2,916,473 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | |||
| Compensation Actually Paid vs. Net Income [Text Block] | |||
| Total Shareholder Return Vs Peer Group [Text Block] | |||
| Tabular List [Table Text Block] | Pay Versus Performance Tabular List We believe the following performance measures represent the most important financial performance measures used by us to link compensation actually paid to our NEOs for the fiscal year ended December 31, 2022: (1) Revenue; (2) EBITDA; (3) Relative TSR; and (4) Net Income. | ||
| Total Shareholder Return Amount | $ 129.17 | 132.09 | 154.48 |
| Peer Group Total Shareholder Return Amount | 102.47 | 133.08 | 116.09 |
| Net Income (Loss) | $ 369,453,000 | $ 292,564,000 | $ 227,128,000 |
| Company Selected Measure Amount | 671,511,000 | 647,408,000 | 553,186,000 |
| PEO Name | Andrew C. Florance | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Revenue | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Compensation Actually Paid vs. Other Measure [Text Block] | |||
| Measure Name | EBITDA | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Relative TSR | ||
| Measure [Axis]: 4 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Net Income | ||
| Measure [Axis]: 5 | |||
| Pay vs Performance Disclosure [Table] | |||
| Non-GAAP Measure Description [Text Block] | Adjusted EBITDA non-GAAP | ||
| PEO [Member] | Deduction for Amounts Reported under the Stock Awards and Option Awards Columns in the 2022 Summary Compensation Table for Applicable Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (15,526,424) | $ (18,710,768) | $ (18,492,242) |
| PEO [Member] | Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Remain Unvested as of Applicable Year End, determined as of Applicable Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 18,416,210 | 14,435,844 | 20,330,911 |
| PEO [Member] | Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Vested during Applicable Year, determined as of Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 3,551 | 0 | 0 |
| PEO [Member] | Increase deduction for Awards Granted during Prior Year(s) that were Outstanding and Unvested as of Applicable Year End, determined based on change in ASC 718 Fair Value from Prior Year End to Applicable Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 756,384 | (3,584,582) | 18,080,010 |
| PEO [Member] | Increase deduction for Awards Granted during Prior Year(s) that Vested During Applicable Year, determined based on change in ASC 718 Fair Value from Prior Year End to Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (6,890,122) | (2,873,898) | 2,198,107 |
| PEO [Member] | Deduction of ASC 718 Fair Value of Awards Granted during Prior Year(s) that were Forfeited during Applicable Year, determined as of Prior Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Total Adjustments [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (3,240,401) | (10,733,404) | 22,116,786 |
| Non-PEO NEO [Member] | Deduction for Amounts Reported under the Stock Awards and Option Awards Columns in the 2022 Summary Compensation Table for Applicable Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (4,293,321) | (5,277,307) | (4,670,083) |
| Non-PEO NEO [Member] | Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Remain Unvested as of Applicable Year End, determined as of Applicable Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 4,567,643 | 3,840,076 | 3,667,266 |
| Non-PEO NEO [Member] | Increase based on ASC 718 Fair Value of Awards Granted during Applicable Year that Vested during Applicable Year, determined as of Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 301 | 530 |
| Non-PEO NEO [Member] | Increase deduction for Awards Granted during Prior Year(s) that were Outstanding and Unvested as of Applicable Year End, determined based on change in ASC 718 Fair Value from Prior Year End to Applicable Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 183,671 | (849,736) | 3,382,952 |
| Non-PEO NEO [Member] | Increase deduction for Awards Granted during Prior Year(s) that Vested During Applicable Year, determined based on change in ASC 718 Fair Value from Prior Year End to Vesting Date [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (1,507,603) | (822,658) | 573,190 |
| Non-PEO NEO [Member] | Deduction of ASC 718 Fair Value of Awards Granted during Prior Year(s) that were Forfeited during Applicable Year, determined as of Prior Year End [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | (5,870,328) |
| Non-PEO NEO [Member] | Total Adjustments [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (1,049,610) | $ (3,109,324) | $ (2,916,473) |
