v2.4.0.8

Investments - Contractual Maturities (Details) (USD $) In Thousands, unless otherwise specified | Jun. 30, 2013 | Dec. 31, 2012
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Schedule of Investments [Line Items] |  |
Due in one year or less, Amortized cost | $ 89,450 |
Due after one year through five years, Amortized cost | 397,591 |
Due after five years through ten years, Amortized cost | 880,828 |
Due after ten years, Amortized cost | 48,766 |
Total before securities without single maturities, Amortized cost | 1,416,635 |
Total Amortized cost | 2,665,870 |
Due in one year or less, Fair value | 90,778 |
Due after one year through five years, Fair value | 419,897 |
Due after five years through ten years, Fair value | 907,750 |
Due after ten years, Fair value | 50,493 |
Total before securities without single maturities, Fair value | 1,468,918 |
Total Investments, Fair Value | 2,714,867 | 2,618,697
Due in one year or less, % of Total fair value | 3.30% |
Due after one year through five years, % of Total fair value | 15.50% |
Due after five years through ten years, % of Total fair value | 33.40% |
Due after ten years, % of Total fair value | 1.90% |
Total before securities without single maturities, % of Total fair value | 54.10% |
% of Total fair value | 100.00% | 100.00%
U.S. agency bonds – mortgage-backed [Member] |  |
Schedule of Investments [Line Items] |  |
Amortized cost of securities without single maturities | 1,221,606 |
Fair value of securities without single maturities | 1,218,486 |
Total Investments, Fair Value | 1,218,486 | 992,174
% of Total fair value for securities without single maturities | 44.90% |
Other mortgage-backed securities [Member] |  |
Schedule of Investments [Line Items] |  |
Amortized cost of securities without single maturities | 27,629 |
Fair value of securities without single maturities | 27,463 |
Total Investments, Fair Value | $ 27,463 | $ 24,068
% of Total fair value for securities without single maturities | 1.00% |

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- Definition Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments. + 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 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 + Details
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- Definition Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments. + 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 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 + Details
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- Definition Amount of available-for-sale debt securities at cost, net of adjustments, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments. + 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 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 + Details
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- Definition Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments. + 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 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 + Details
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