4. Fair Value and Cost of Securities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
U.S. government and agency	$ 216,518	$ 175,328
State and political subdivision	110,637	82,397
Foreign government	48,616	31,877
Corporate	1,537,944	1,208,377
Residential mortgage-backed (“RMBS”)	525,888	553,519
CDO/CLO	62,521	68,016
Other asset-backed	132,938	136,923
Available-for-sale debt securities	2,913,202	2,546,392
Amortized Cost
U.S. government and agency	203,205	163,132
State and political subdivision	99,773	77,323
Foreign government	44,423	30,473
Corporate	1,462,223	1,169,209
Commercial mortgage-backed (“CMBS”)	261,834	281,616
Residential mortgage-backed (“RMBS”)	525,183	562,186
CDO/CLO	71,211	77,456
Other asset-backed	129,549	135,435
Available-for-sale debt securities	2,797,401	2,496,830
Gross Unrealized Gains
U.S. government and agency	13,686	12,653
State and political subdivision	11,351	5,518
Foreign government	4,255	1,825
Corporate	114,901	83,310
Commercial mortgage-backed (“CMBS”)	18,862	12,283
Residential mortgage-backed (“RMBS”)	18,718	14,106
CDO/CLO	1,398	1,240
Other asset-backed	3,959	2,333
Available-for-sale debt securities	187,130	133,268
Gross Unrealized Loss
U.S. government and agency	(373)	(457)
State and political subdivision	(487)	(444)
Foreign government	(62)	(421)
Corporate	(39,180)	(44,142)
Commercial mortgage-backed (“CMBS”)	(2,556)	(3,944)
Residential mortgage-backed (“RMBS”)	(18,013)	(22,773)
CDO/CLO	(10,088)	(10,680)
Other asset-backed	(570)	(845)
Available-for-sale debt securities	(71,329)	(83,706)
Fair Value
U.S. government and agency	216,518	175,328
State and political subdivision	110,637	82,397
Foreign government	48,616	31,877
Corporate	1,537,944	1,208,377
Commercial mortgage-backed (“CMBS”)	278,140	289,955
Residential mortgage-backed (“RMBS”)	525,888	553,519
CDO/CLO	62,521	68,016
Other asset-backed	132,938	136,923
Available-for-sale debt securities	2,913,202	2,546,392
OTTI Recognized In AOCI
U.S. government and agency	0	0
State and political subdivision	0	0
Foreign government	0	0
Corporate	(1,505)	(1,505)
Commercial mortgage-backed (“CMBS”)	(650)	(5,131)
Residential mortgage-backed (“RMBS”)	(21,660)	(20,396)
CDO/CLO	(6,132)	(6,220)
Other asset-backed	0	0
Available-for-sale debt securities	$ (29,947)	$ (33,252)

Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References+ Details

Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

-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.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-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.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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-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.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-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.

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+ Details

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents securitized, pay-through debt securities collateralized by real estate mortgage loans (mortgages) as of the balance sheet date which have been categorized as available-for-sale.

+ References+ Details

- Definition

Bonds or similar securities issued by state, city, or local governments or the agencies operated by state, city, or local governments which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References+ Details