Fair Value Measurements (Summarize Changes in Level 3 Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Beginning Balance	$ 62,022	$ 82,541
Earnings	154	(3,905)
Other Comprehensive Income	(91)	11,455
Purchases	14,297	283
(Sales)	(14,425)	(11,274)
Maturities	(3,467)	(17,171)
Transfer out	0	93
Ending Balance	58,490	62,022
Fixed Maturities Securities [Member]
Beginning Balance	59,065	67,828
Earnings	(15)	(1,497)
Other Comprehensive Income	144	9,622
Purchases	14,297	283
(Sales)	(14,255)	0
Maturities	(3,467)	(17,171)
Transfer out	0	0
Ending Balance	55,769	59,065
Equity Securities Available For Sale [Member]
Beginning Balance	2,029	13,862
Earnings	0	1,126
Other Comprehensive Income	(235)	(1,737)
Purchases	0	0
(Sales)	(170)	(11,222)
Maturities	0	0
Transfer out	0	0
Ending Balance	1,624	2,029
Securities Sold But Not Yet Purchased [Member]
Beginning Balance	20	21
Earnings	(18)	(1)
Other Comprehensive Income	0	0
Purchases	0	0
(Sales)	0	0
Maturities	0	0
Transfer out	0	0
Ending Balance	2	20
Corporate [Member] \| Fixed Maturities Securities [Member]
Beginning Balance	59,065	67,828
Earnings	(15)	(1,497)
Other Comprehensive Income	144	9,622
Purchases	14,297	283
(Sales)	(14,255)	0
Maturities	(3,467)	(17,171)
Transfer out	0	0
Ending Balance	55,769	59,065
Common Stock [Member] \| Equity Securities Available For Sale [Member]
Beginning Balance	1,408	1,559
Earnings	0	0
Other Comprehensive Income	0	0
Purchases	0	0
(Sales)	(170)	151
Maturities	0	0
Transfer out	0	0
Ending Balance	1,238	1,408
Preferred Stock [Member] \| Equity Securities Available For Sale [Member]
Beginning Balance	621	12,303
Earnings	0	1,126
Other Comprehensive Income	(235)	(1,737)
Purchases	0	0
(Sales)	0	(11,071)
Maturities	0	0
Transfer out	0	0
Ending Balance	386	621
Arbitrage Trading Account [Member]
Beginning Balance	928	851
Earnings	169	(3,534)
Other Comprehensive Income	0	3,570
Purchases	0	0
(Sales)	0	52
Maturities	0	0
Transfer out	0	93
Ending Balance	$ 1,097	$ 928

Amount of gain (loss) recognized in earnings, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) recognized in other comprehensive income, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents [net] transfers in to and out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant