Related Party Transactions - AgFirst Farm Credit Bank (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Zions First National Bank [Member] \| Medium-term Notes [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 0	$ 0	$ 5,000,000
AgFirst Farm Credit Bank [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties	1,100,000	1,200,000	1,300,000
Accounts Receivable, Related Parties, Current	100,000	100,000
Related Party Transaction, Other Revenues from Transactions with Related Party	0	100,000	100,000
CFC [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	741,895,000	1,310,599,000	903,465,000
Revenue from Related Parties	2,000,000	500,000	0
Accounts Receivable, Related Parties, Current	200,000	100,000
Related Party Transaction, Other Revenues from Transactions with Related Party	$ 100,000	$ 81,954	84,260
Common Class B, Voting [Member] \| AgFirst Farm Credit Bank [Member]
Related Party Transaction [Line Items]
Common Stock Ownership Percentage by a Related Party	16.80%
Common Class B, Voting [Member] \| CoBank, ACB [Member]
Related Party Transaction [Line Items]
Common Stock Ownership Percentage by a Related Party		32.60%
Guarantee Obligations [Member] \| AgFirst Farm Credit Bank [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	$ 36,400,000	$ 28,500,000	$ 19,700,000
Related Party Transactions, Outstanding Balance	331,300,000	320,700,000
Performance Guarantee [Member] \| AgFirst Farm Credit Bank [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Outstanding Balance	19,700,000	24,600,000
Floating Interest Rate [Member] \| Subordinated Debt [Member] \| CoBank, ACB [Member]
Related Party Transaction [Line Items]
Notes Receivable, Related Parties	$ 70,000,000	$ 70,000,000

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- Definition

Related Party Transactions, Outstanding Balance

+ References

No definition available.

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- Definition

Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

For an unclassified balance sheet, amounts due from parties associated with the reporting entity as evidenced by a written promise to pay.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
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- Definition

Amount of transactions with related party during the financial reporting period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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.

+ References

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- Definition

Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

+ References

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- Definition

Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

No definition available.

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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