Fair Value (Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 6,127	$ 52,030
Total gains or (losses) (realized/unrealized) Included in earnings	1,661	(431)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(5,869)	(1,521)
Purchases, issuances and settlements	64,945	2,433
Transfers in and/or (out) of Level 3	(51,101)	(46,384)
Ending balance	15,763	6,127
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	42
Purchases, issuances and settlements	1,274
Transfers in and/or (out) of Level 3	(1,316)
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Asset-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	5,299	4,849
Total gains or (losses) (realized/unrealized) Included in earnings	1,259	258
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(126)	(717)
Purchases, issuances and settlements	21,303	(624)
Transfers in and/or (out) of Level 3	(27,735)	1,533
Ending balance		5,299
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(426)
Purchases, issuances and settlements	9,023
Ending balance	8,597
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Foreign Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	481	11,913
Total gains or (losses) (realized/unrealized) Included in earnings	73	(738)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(5,221)	(587)
Purchases, issuances and settlements	4,038	2,858
Transfers in and/or (out) of Level 3	7,795	(12,965)
Ending balance	7,166	481
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Foreign Government Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or (losses) (realized/unrealized) Included in earnings		(112)
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)		(179)
Purchases, issuances and settlements		516
Transfers in and/or (out) of Level 3		(225)
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Non-Agency Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	347	426
Total gains or (losses) (realized/unrealized) Included in earnings	329	161
Total gains or (losses) (realized/unrealized) Included in other comprehensive income (loss)	(138)	(38)
Purchases, issuances and settlements	(538)	(317)
Transfers in and/or (out) of Level 3		115
Ending balance		347
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date
Agency Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance		34,842
Purchases, issuances and settlements	29,845
Transfers in and/or (out) of Level 3	(29,845)	(34,842)
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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

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-Name Accounting Standards Codification

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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