Cash and Cash Equivalents - Additional Information (Detail)	9 Months Ended
Sep. 30, 2017
Cash And Cash Equivalents [Abstract]
Liquid investments maturity date	Three months or less

Highly liquid investments maturity period description.

No definition available.

Name:	fmi_HighlyLiquidInvestmentsMaturityPeriodDescription
Namespace Prefix:	fmi_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration