Off-Balance Sheet Guarantees and Long Term Standby Purchase Commitments - Off-Balance Sheet Guaranteed Securities (Details) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Guarantor Obligations [Line Items] | ||
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 1,809,194 | $ 1,636,592 |
| Farm & Ranch [Member] | ||
| Guarantor Obligations [Line Items] | ||
| Guarantor Obligations, Maximum Exposure, Undiscounted | 514,051 | 636,086 |
| USDA Guarantees [Member] | ||
| Guarantor Obligations [Line Items] | ||
| Guarantor Obligations, Maximum Exposure, Undiscounted | 10,272 | 13,978 |
| Institutional Credit [Member] | ||
| Guarantor Obligations [Line Items] | ||
| Guarantor Obligations, Maximum Exposure, Undiscounted | 984,871 | 986,528 |
| Revolving Credit Facility [Member] | Institutional Credit [Member] | ||
| Guarantor Obligations [Line Items] | ||
| Guarantor Obligations, Maximum Exposure, Undiscounted | $ 300,000 | $ 0 |