Investment Securities Investment Securities (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Investments
Amortized Cost	$ 80,538	$ 80,538
Gross Unrealized Gains	12,016	7,402
Gross Unrealized Losses	0	0
Fair Value	92,554	87,940
Preferred Stock \| Farmer Mac—Series A Non-Cumulative Preferred Stock
Investments
Amortized Cost	30,000	30,000
Gross Unrealized Gains	1,585	780
Gross Unrealized Losses	0	0
Fair Value	31,585	30,780
Preferred Stock \| Farmer Mac—Series B Non-Cumulative Preferred Stock
Investments
Amortized Cost	25,000	25,000
Gross Unrealized Gains	1,940	2,600
Gross Unrealized Losses	0	0
Fair Value	26,940	27,600
Preferred Stock \| Farmer Mac—Series C Non-Cumulative Preferred Stock
Investments
Amortized Cost	25,000	25,000
Gross Unrealized Gains	4,150	1,650
Gross Unrealized Losses	0	0
Fair Value	29,150	26,650
Common Stock \| Farmer Mac—Class A Common Stock
Investments
Amortized Cost	538	538
Gross Unrealized Gains	4,341	2,372
Gross Unrealized Losses	0	0
Fair Value	$ 4,879	$ 2,910

Line items represent reporting 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Section 50
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 2
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 2
-Subparagraph (c)
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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 210.5-02.2)
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