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Derivatives (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Derivative [Line Items] |  |  |
Derivative liabilities | $ 74,935 | $ 82,323 |
Net reductions to interest expense related to net settlements of derivatives | 1,000 | 3,000 | $ 3,600
Derivative assets | 66,146 | 83,780 |
Collateral posted | 28,796 | 36,349 |
Credit-Risk-Related Contingent Features |  |  |
Derivative [Line Items] |  |  |
Aggregate fair value of derivative instruments in net liability position | 6,300 | 7,100 |
Collateral posted | 6,200 | 9,100 |
Derivative instruments designated as hedging instruments |  |  |
Derivative [Line Items] |  |  |
Notional amount | 35,811 | 131,391 |
Derivative liabilities | 6,799 | 5,976 |
Derivative assets | 0 | 4,325 |
Derivative instruments designated as hedging instruments | Interest rate swaps on certificates of deposit |  |  |
Derivative [Line Items] |  |  |
Notional amount | 35,811 | 48,365 |
Derivative liabilities | 6,799 | 5,976 |
Derivative assets | 0 | 0 |
Derivative instruments designated as hedging instruments | Foreign currency forward contracts |  |  |
Derivative [Line Items] |  |  |
Notional amount | 0 | 83,026 |
Derivative liabilities | 0 | 0 |
Derivative assets | 0 | 4,325 |
Derivative instruments not designated as hedging instruments |  |  |
Derivative [Line Items] |  |  |
Notional amount | 10,153,108 | 8,507,660 |
Derivative liabilities | 68,136 | 76,347 |
Derivative assets | 66,146 | 79,455 |
Derivative instruments not designated as hedging instruments | Public Companies |  |  |
Derivative [Line Items] |  |  |
Derivative assets | 993 |  |
Derivative instruments not designated as hedging instruments | Interest rate swaps and options |  |  |
Derivative [Line Items] |  |  |
Notional amount | 9,333,860 | 7,668,482 |
Derivative liabilities | 57,958 | 65,131 |
Derivative assets | 58,633 | 67,578 |
Notional amount of derivative assets | 4,690,000 | 3,860,000 |
Notional amount of derivative liabilities | 4,650,000 | 3,810,000 |
Derivative instruments not designated as hedging instruments | Credit risk participation agreements (“RPAs”) |  |  |
Derivative [Line Items] |  |  |
Notional amount | 49,033 | 71,414 |
Derivative liabilities | 8 | 3 |
Derivative assets | $ 1 | $ 3 |
Weighted average remaining maturity | 6 years | 3 years 8 months |
Derivative instruments not designated as hedging instruments | Credit risk participation agreements (“RPAs”) | Long |  |  |
Derivative [Line Items] |  |  |
Notional amount | $ 35,200 | $ 48,300 |
Derivative liabilities | 8 | 3 |
Interest rate derivative exposure | 419 | 179 |
Derivative instruments not designated as hedging instruments | Credit risk participation agreements (“RPAs”) | Short |  |  |
Derivative [Line Items] |  |  |
Notional amount | 13,800 | 23,100 |
Derivative assets | $ 1 | 3 |
Derivative instruments not designated as hedging instruments | Foreign exchange options |  |  |
Derivative [Line Items] |  |  |
Term of contract (in years) | 5 years |  |
Derivative instruments not designated as hedging instruments | Private Companies |  |  |
Derivative [Line Items] |  |  |
Derivative assets | $ 679 |  |
Derivative instruments not designated as hedging instruments | Warrants |  |  |
Derivative [Line Items] |  |  |
Notional amount | 0 | 0 |
Derivative liabilities | 0 | 0 |
Derivative assets | $ 1,672 | $ 0 |

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