Long Term Subordinated Notes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Percentage of principal amount required for redemption	100.00%
Long Term Subordinated Debt [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	6.60%	6.60%
Percentage of principal amount required for redemption	100.00%
Outstanding debt reduction	$ 161,441
Debt instrument, maturity date	May 01, 2067	May 01, 2067
Long Term Subordinated Debt [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Applicable spread on treasury rate	0.25%
Long Term Subordinated Debt [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Applicable spread on treasury rate	0.50%
Parent Company [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	1.72%
Debt instrument, maturity date	Dec. 31, 2023
Fixed Rate Interest Period [Member] \| Long Term Subordinated Debt [Member]
Debt Instrument [Line Items]
Interest basis, 3 month LIBOR plus number of basis points, reset quarterly	2.385%
Fixed Rate Interest Period [Member] \| Long Term Subordinated Debt [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Right to defer interest on one or more occasions for up to number of consecutive years	10 years
Floating Rate Interest Period [Member]
Debt Instrument [Line Items]
Floating rate terms	interest will be based on the 3 month LIBOR plus 238.5 basis points, reset quarterly, payable quarterly in arrears on February 15, May 15, August 15 and November 15 of each year, subject to Holdings' right to defer interest on one or more occasions for up to ten consecutive years.
Floating Rate Interest Period [Member] \| Long Term Subordinated Debt [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Right to defer interest on one or more occasions for up to number of consecutive years	10 years
Senior Notes 5.4% [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.40%
Debt instrument, maturity date	Oct. 15, 2014
Senior Notes 4.868% [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.868%	4.868%
Debt instrument, maturity date	Jun. 01, 2044	Jun. 01, 2044

Debt Instrument, Discount Rate Terms

No definition available.

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- Definition

Debt Instrument Periodic Payment Interest Right Of Deferment Number Of Years

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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- Definition

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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- 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.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

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- Definition

The cash outflow from the repayment of long-term borrowing where a lender is placed in a lien position behind debt having a higher priority of repayment (senior) in case of liquidation of the entity's assets or underlying collateral.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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