Postretirement Benefits (Details Textual)	12 Months Ended
	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Postretirement Benefits Description Of Medical Coverage	First Federal employees who retired prior to April1, 1997 and who completed 20 years of service after age 40 receive full medical coverage at no cost.
Percentage Of Eligible Coverage In Postretirement Benefits	10.00%
Maximum Reimburse Medical Expenses	$ 10,000
Other Comprehensive Income Loss Defined Benefit Plan Expected To Be Recognized In Net Postretirement Benefit Cost Before Tax	10,000
Other Comprehensive Income Loss Defined Benefit Plan Expected To Be Recognized In Net Postretirement Benefit Cost Net Of Tax	7,000
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax, Total	12,000
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, Net of Tax	8,000
Defined Benefits Plan, Expected Contribution, Before Reflecting Subsidy Payments	$ 160,000
Postretirement Benefits Description Of Medical Coverage One	First Federal employees who were born after December 31, 1950 are not eligible for the medical coverage described above at retirement.