Annual report pursuant to Section 13 and 15(d)

Employees' Benefit Plans (Details Textual)

v3.3.1.900
Employees' Benefit Plans (Details Textual) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Jun. 30, 2014
Jun. 30, 2013
Defined Benefit Plan Disclosure [Line Items]        
Eligibility Of Employees Employees are eligible to participate in the Employees Savings and Profit Sharing Plan and Trust on the next January 1 or July 1 following the completion of one year of employment, attaining age 18, and completion of 1,000 hours of service.      
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay 8.00% 8.00%    
Defined Contribution Plan, Cost Recognized $ 705 $ 599    
Deferred Compensation Liability, Current and Noncurrent 188 171    
Deferred Compensation Arrangement with Individual, Compensation Expense 17 15    
Deferred Costs 97 106    
Deferred Fee Liability $ 1,340 $ 1,300    
Defined Benefit Plan, Funded Percentage 91.47% 94.17%    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities $ 1,500      
Trust for Benefit of Employees [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Description of Defined Contribution Pension and Other Postretirement Plans Participants also become 100% vested in the employer contributions and accrued earnings in their account upon their death, approved disability, or attainment of age 65 while employed at the Bank.      
Two Years Of Service [Member] | Trust for Benefit of Employees [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Funded Percentage 40.00%      
Three Years Of Service [Member] | Trust for Benefit of Employees [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Funded Percentage 60.00%      
Four Years Of Service [Member] | Trust for Benefit of Employees [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Funded Percentage 80.00%      
Five Years Of Service [Member] | Trust for Benefit of Employees [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Funded Percentage 100.00%      
Pentegra DB Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Contribution Plan, Cost Recognized     $ 190,800 $ 136,500
Maximum [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan Employees Pre Tax Contributions 50.00%      
Minimum [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan Employees Pre Tax Contributions 1.00%