Repurchase Agreements and Other Advances (Repricing Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	$ 7,879,087	$ 6,614,701
Repurchase agreements
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	7,879,114	6,614,907
Less debt issuance costs	27	206
Total repurchase agreements less debt issuance costs	$ 7,879,087	$ 6,614,701
Weighted Average Interest Rate	3.42%	2.42%
Within 30 days \| Repurchase agreements
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	$ 6,747,166	$ 6,161,008
Weighted Average Interest Rate	3.35%	2.39%
Over 30 days to 3 months \| Repurchase agreements
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	$ 368,857	$ 453,899
Weighted Average Interest Rate	3.10%	2.76%
Over 3 months to 12 months \| Repurchase agreements
Debt Securities, Available-for-sale [Line Items]
Repurchase agreements	$ 763,091	$ 0
Weighted Average Interest Rate	4.18%	0.00%

Securities Sold Under Agreements To Repurchase, Net of Debt Issuance Costs

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- Definition

Interest rate on the amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(A)(ii))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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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

No definition available.

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- Definition

Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

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