Qualifying Debt - Junior Subordinated Debt (Details) $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($) Trust	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Number of statutory businesses formed or acquired \| Trust	8
Carrying value of junior subordinated debt \| $	$ 61.0	$ 58.4
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Weighted average interest rate (percent)	3.19%	2.95%
London Interbank Offered Rate (LIBOR) [Member] \| Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Spread on variable rate (percent)	2.34%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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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.

+ Details

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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://www.xbrl.org/2003/role/presentationRef
-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://www.xbrl.org/2003/role/presentationRef
-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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of long-term debt outstanding.

+ References

No definition available.

+ Details

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- Definition

Number of Statutory Business Trusts Formed or Acquired

+ References

No definition available.

+ Details

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- Details

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- Details

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