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Fair Value Of Financial Instruments (Schedule Of Changes In Fair Value Associated With Level 3 Financial Instruments) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Transfers, Into Level 3 | $ 500 |
Transfers, Out of Level 3 | (3,000) |
Non-Agency [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 1,476 | $ 806
Unrealized gains/(losses), Included in changes in net assets | (18) | (241)
Realized gains/(losses) | 54 | 127
Redemptions | (430) | (332)
Transfers, Into Level 3 |  | 1,116
Net change | (394) | 670
Ending Balance | 1,082 | 1,476
Corporate Fixed Income Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance |  | 1,993
Unrealized gains/(losses), Included in changes in net assets |  | 84
Realized gains/(losses) |  | 53
Purchases | 292 | 11,643
Sales |  | (13,773)
Redemptions | (19) |
Net change | 273 | (1,993)
Ending Balance | 273 |
Equity Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 619 | 1,144
Unrealized gains/(losses), Included in changes in net assets | (279) |
Purchases | 253 |
Sales |  | (525)
Transfers, Into Level 3 | 7 |
Net change | (19) | (525)
Ending Balance | 600 | 619
Corporate Equity Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 2,942 | 7,550
Unrealized gains/(losses), Included in changes in net assets | (361) | 1,410
Realized gains/(losses) | 2,453 |
Purchases | 3,593 |
Redemptions | (4,794) |
Transfers, Into Level 3 |  | 182
Transfers, Out of Level 3 |  | (6,200)
Net change | 891 | (4,608)
Ending Balance | 3,833 | 2,942
Equity Auction Rate Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 50,442 | 46,197
Unrealized gains/(losses), Included in changes in net assets | 547 | (413)
Purchases | 50 | 15,176
Redemptions | (2,350) | (5,250)
Transfers, Out of Level 3 |  | (5,268)
Net change | (1,753) | 4,245
Ending Balance | 48,689 | 50,442
Auction Rate Municipal Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 1,315 | 1,326
Unrealized gains/(losses), Included in changes in net assets | 67 | (11)
Redemptions | (550) |
Net change | (483) | (11)
Ending Balance | 832 | 1,315
Other Investment [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance | 20 | 2,026
Unrealized gains/(losses), Included in changes in net assets |  | (938)
Purchases | 3,782 |
Transfers, Into Level 3 | 465 |
Transfers, Out of Level 3 | (3,027) | (1,068)
Net change | 1,220 | (2,006)
Ending Balance | $ 1,240 | 20
Asset-Backed Securities [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |
Beginning Balance |  | 44,045
Unrealized gains/(losses), Included in OCI, Assets |  | 342
Realized gains/(losses) |  | (2,136)
Sales |  | (42,251)
Net change |  | $ (44,045)

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- Definition 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 -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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