The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12b
-Subsection 1

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The interest rate used to adjust for the time value of money for the plan.

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The interest rate used to adjust for the time value of money.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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Amount of contributions made by the employer to defined benefit plans.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(ii)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 35
-Paragraph 123
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-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(01)
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Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

Three digit plan number for a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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- Definition

Description of the significant collective-bargaining arrangements within the range of expiration dates for collective-bargaining arrangements requiring contributions to a multiemployer plan as well as other information to help investors understand the significance of the collective-bargaining agreements and when they expire. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Indicate whether the multiemployer plan is less than 65 percent funded, between 65 and less than 80 percent funded, or at least 80 percent funded. The acceptable values are: (1) "less than 65 percent", (2) "between 65 and less than 80 percent", (3) "at least 80 percent", and (4) "NA". A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Indicate whether a funding improvement plan or rehabilitation plan has been implemented or is pending for a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "pending", "implemented", "other", and "NA".

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount of minimum contribution(s) required for future periods to a multiemployer plan by collective bargaining arrangements, statutory obligations, or other contractual obligations. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Indicate whether the employer paid a surcharge to the pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "yes", and "NA".

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EMPLOYEE BENEFIT PLANS (Details) - USD ($)	12 Months Ended
EMPLOYEE BENEFIT PLANS (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plan [Member]
Multiemployer Plans [Line Items]
Multiemployer Plans, Funded Status	At least 80 percent	At least 80 percent
FIP/RP Status Pending/Implemented	No
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	N/A
Minimum Contributions Required for Future Periods	$ 0
Pension Plan [Member] \| Pentegra Defined Benefit Plan for Financial Institutions [Member]
Multiemployer Plans [Line Items]
Entity Tax Identification Number	135645888
Pension Plan Number	333
Minimum [Member]
Multiemployer Plans [Line Items]
Discount rate used for benefit obligation	2.49%	2.49%	2.24%
Discount rate used for net periodic benefit cost	2.49%	2.24%	2.43%
Maximum [Member]
Multiemployer Plans [Line Items]
Discount rate used for benefit obligation	3.94%	4.16%	3.84%
Discount rate used for net periodic benefit cost	4.16%	3.84%	4.76%
Supplemental Executive Retirement Plans [Member]
Multiemployer Plans [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 14,177,000	$ 13,290,000	$ 12,537,000	$ 8,243,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	471,000
Contributions paid	320,000	$ 276,000	$ 271,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	$ 466,000