The average effective interest rate during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

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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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
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Junior Subordinated Deferrable Interest Debentures (Key Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Nov. 01, 2016	Dec. 31, 2015	Jul. 29, 2015
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 160,416,000		$ 161,416,000
Trust VI
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,774,000
Interest rate (as a percent)	4.36%
Interest rate index	3.45
Trust VIII
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,774,000
Interest rate (as a percent)	3.93%
Interest rate index	3.05
Trust IX
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 41,238,000
Interest rate (as a percent)	2.47%
Interest rate index	1.62
Trust X
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 21,021,000			$ 34,021,000
Interest rate (as a percent)	2.54%
Interest rate index	1.65
Trust XI
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,990,000	$ 26,990,000		$ 27,990,000
Interest rate (as a percent)	2.47%
Interest rate index	1.62
Trust XII
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 20,619,000
Interest rate (as a percent)	2.38%
Interest rate index	1.45
Parent Company
Junior subordinated deferrable interest debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 160,416,000		$ 161,416,000