XML 58 R40.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 08, 2015
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Sale of minority interest percentage | 75.00% |  |  |
Cash and cash equivalents maturity description |  | 90 |  |
Additional amounts to be paid in cash or common stock based on achievement of performance measures within period, maximum years |  | 5 years |  |
Money market funds fair value |  | $ 9.2 | $ 12.4 |
Cash surrender fair value of life insurance |  | 15.6 | 15.8 |
Contingent consideration liabilities related to acquisitions |  | $ 30.5 | $ 17.3 |
5.25% Senior Unsecured Notes Due 2023 [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Debt instrument interest rate |  |  |  | 5.25%
Unnamed Corporate Joint Venture [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Equity method ownership percentage in joint venture |  | 37.50% |  |
Government Contracts Concentration Risk [Member] | Accounts Receivable [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Percentage of net accounts receivable |  | 17.00% | 17.00% |
Buildings [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 30 years |  |
Maximum [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Long-term investments maturity period, in years |  | 6 years |  |
Short-Term investments maturity period, in years |  | 1 year |  |
Intangible assets finite lives |  | 20 years |  |
Maximum [Member] | Medical Equipment [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 7 years |  |
Maximum [Member] | Computer Equipment [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 7 years |  |
Maximum [Member] | Software and Software Development Costs [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 7 years |  |
Maximum [Member] | Furniture [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 7 years |  |
Minimum [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Long-term investments maturity period, in years |  | 1 year |  |
Intangible assets finite lives |  | 1 year |  |
Minimum [Member] | Medical Equipment [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 3 years |  |
Minimum [Member] | Computer Equipment [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 3 years |  |
Minimum [Member] | Software and Software Development Costs [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 3 years |  |
Minimum [Member] | Furniture [Member] |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Property and equipment estimated useful lives, years |  | 3 years |  |

X
- Definition Business combination, contingent consideration arrangements, time period. + References No definition available. + Details
Name: | md_BusinessCombinationContingentConsiderationArrangementsTimePeriod
Namespace Prefix: | md_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cash and cash equivalents maturity description. + References No definition available. + Details
Name: | md_CashAndCashEquivalentsMaturityDescription
Namespace Prefix: | md_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Long term investments maturity period. + References No definition available. + Details
Name: | md_LongTermInvestmentsMaturityPeriod
Namespace Prefix: | md_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Money market funds at fair value. + References No definition available. + Details
Name: | md_MoneyMarketFundsAtFairValue
Namespace Prefix: | md_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sale of minority interest percentage. + References No definition available. + Details
Name: | md_SaleOfMinorityInterestPercentage
Namespace Prefix: | md_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Short term investment maturity period. + References No definition available. + Details
Name: | md_ShortTermInvestmentMaturityPeriod
Namespace Prefix: | md_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary of significant accounting policies. + References No definition available. + Details
Name: | md_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | md_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount, measured at acquisition-date fair value, of all liabilities assumed that arise from contingencies and were recognized by the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472 + Details
Name: | us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI). + References No definition available. + Details
Name: | us-gaap_CashSurrenderValueFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CreditFacilityAxis=md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=md_UnnamedCorporateJointVentureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_GovernmentContractsConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_ComputerEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_SoftwareAndSoftwareDevelopmentCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |