Accounts Payable and Accrued Expenses - Additional Information (Detail) $ in Millions	9 Months Ended
Sep. 30, 2020 USD ($)
Net decrease in accrued salaries and bonuses	$ 35.1

Increase decrease in accrued salaries and bonuses.

No definition available.

Name:	md_IncreaseDecreaseInAccruedSalariesAndBonuses
Namespace Prefix:	md_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration