Derivative Financial Instruments - Carrying values (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivatives not designated as hedging instruments
Mortgage Banking Derivatives Assets, Carrying Value	$ 1,392	$ 367
Mortgage Banking Derivatives Liabilities, Carrying Value	205	73
Mortgage Banking Derivatives, Derivatives Net Carrying Value	$ 1,187	$ 294

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:	fdef_DerivativeAssetsCarryingValue
Namespace Prefix:	fdef_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant