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Cover Page - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 | Feb. 14, 2020 | Jun. 28, 2019
Cover [Abstract] |  |  |
Document Type | 10-K |  |
Document Annual Report | true |  |
Document Transition Report | false |  |
Amendment Flag | false |  |
Document Period End Date | Dec. 31, 2019 |  |
Document Fiscal Year Focus | 2019 |  |
Document Fiscal Period Focus | FY |  |
Entity Registrant Name | MEDNAX, INC. |  |
Entity Central Index Key | 0000893949 |  |
Current Fiscal Year End Date | --12-31 |  |
Entity Well-known Seasoned Issuer | Yes |  |
Entity Current Reporting Status | Yes |  |
Entity Interactive Data Current | Yes |  |
Entity Common Stock, Shares Outstanding |  | 84,277,494 |
Entity Voluntary Filers | No |  |
Title of 12(b) Security | Common Stock |  |
Trading Symbol | MD |  |
Security Exchange Name | NYSE |  |
Entity File Number | 001-12111 |  |
Entity Incorporation, State or Country Code | FL |  |
Entity Tax Identification Number | 26-3667538 |  |
Entity Address, Address Line One | 1301 Concord Terrace |  |
Entity Address, City or Town | Sunrise |  |
Entity Address, State or Province | FL |  |
Entity Address, Postal Zip Code | 33323 |  |
City Area Code | 954 |  |
Local Phone Number | 384-0175 |  |
Entity Filer Category | Large Accelerated Filer |  |
Entity Small Business | false |  |
Entity Emerging Growth Company | false |  |
Entity Shell Company | false |  |
Entity Public Float |  |  | $ 2,051,190,371

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