Derivative Financial Instruments - Carrying values (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivatives not designated as hedging instruments
Mortgage Banking Derivatives Assets, Carrying Value	$ 7,913	$ 883
Mortgage Banking Derivatives (Liabilities), Carrying Value		(9)
Mortgage Banking Derivatives, Derivatives Net Carrying Value	$ 7,913	$ 892

Carrying values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

No definition available.

Name:	pfc_DerivativeAssetsCarryingValue
Namespace Prefix:	pfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant