Offsetting of Assets and Liabilities (Details) - USD ($) $ in Thousands |
Mar. 31, 2019 |
Dec. 31, 2018 |
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|---|---|---|---|---|---|---|---|---|---|
| Financial derivatives–assets | |||||||||
| Financial derivatives–assets, at fair value- | [1] | $ 15,356 | $ 20,001 | ||||||
| Financial Instruments Available for Offset | (12,082) | (10,910) | |||||||
| Cash Collateral (Received) Pledged | [2],[3] | (1,232) | (2,514) | ||||||
| Net Amount | 2,042 | 6,577 | |||||||
| Reverse repurchase agreements | |||||||||
| Amount of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheet(1) | [1] | 25,381 | 61,274 | ||||||
| Financial Instruments Available for Offset | (25,381) | (61,274) | |||||||
| Cash Collateral (Received) Pledged | [2],[3] | 0 | 0 | ||||||
| Net Amount | 0 | 0 | |||||||
| Repurchase agreements | |||||||||
| Amount of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheet(1) | [1] | (1,550,016) | (1,498,849) | ||||||
| Financial Instruments Available for Offset | 25,381 | 61,274 | |||||||
| Cash Collateral (Received) Pledged | [2],[3] | 13,873 | 16,974 | ||||||
| Net Amount | 0 | 0 | |||||||
| Financial derivatives–liabilities | |||||||||
| Amount of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheet(1) | [1] | (26,904) | (20,806) | ||||||
| Financial Instruments Available for Offset | 12,082 | 10,910 | |||||||
| Cash Collateral (Received) Pledged | [2],[3] | 10,373 | 9,896 | ||||||
| Net Amount | (4,449) | 0 | |||||||
| Securities Collateral relating to Reverse Repurchase Agreements | 1,850,000 | 1,790,000 | |||||||
| Financial Derivatives - Assets | |||||||||
| Financial derivatives–assets | |||||||||
| Financial derivatives–assets, at fair value- | 20,001 | ||||||||
| Financial Instruments Transferred or Pledged as Collateral | [2],[3] | 0 | 0 | ||||||
| Financial derivatives–liabilities | |||||||||
| Excess cash collateral | 3,000 | 100 | |||||||
| Repurchase Agreements [Member] | |||||||||
| Financial derivatives–assets | |||||||||
| Financial Instruments Transferred or Pledged as Collateral | [2],[3] | 0 | 0 | ||||||
| Reverse repurchase agreements | |||||||||
| Amount of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheet(1) | 61,274 | ||||||||
| Financial Derivatives - Liabilities | |||||||||
| Financial derivatives–assets | |||||||||
| Financial Instruments Transferred or Pledged as Collateral | [2],[3] | 0 | 0 | ||||||
| Financial derivatives–liabilities | |||||||||
| Amount of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheet(1) | 20,806 | ||||||||
| Excess cash collateral | 13,800 | 16,400 | |||||||
| Reverse repurchase agreements | |||||||||
| Financial derivatives–assets | |||||||||
| Financial Instruments Transferred or Pledged as Collateral | [2],[3] | $ 1,510,762 | $ 1,420,601 | ||||||
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