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Junior Subordinated Deferrable Interest Debentures (Key Information) (Details) - USD ($) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2018 | Dec. 31, 2017
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 160,416 | $ 160,416
Trust VI |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 25,774 |
Interest rate (as a percent) | 5.76% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 3.45% |
Trust VIII |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 25,774 |
Interest rate (as a percent) | 5.39% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 3.05% |
Trust IX |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 41,238 |
Interest rate (as a percent) | 3.96% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 1.62% |
Trust X |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 21,021 |
Interest rate (as a percent) | 3.99% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 1.65% |
Trust XI |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 25,990 |
Interest rate (as a percent) | 3.96% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 1.62% |
Trust XII |  |
Junior subordinated deferrable interest debentures, major types of business trusts |  |
Junior subordinated deferrable interest debentures | $ 20,619 |
Interest rate (as a percent) | 3.77% |
Interest rate index | LIBOR |
Spread on interest rate index (as a percent) | 1.45% |

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- Definition Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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