Fair Value (Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 9,795	$ 2,532	$ 15,763	$ 4,018
Total gains or (losses) (realized/unrealized), Included in earnings	56	1,237	175	1,312
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	(1,380)	(295)	(1,311)	(222)
Purchases, issuances and settlements	1,723	22,783	3,651	21,149
Transfers in and/or (out) of Level 3	1,206	(1,101)	(6,878)	(1,101)
Ending balance	11,400	$ 25,156	11,400	$ 25,156
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 Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	1,958
Total gains or (losses) (realized/unrealized), Included in earnings	(6)		(2)
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	(93)	$ 42	(95)	$ 42
Purchases, issuances and settlements	1,723	1,274	3,651	1,274
Transfers in and/or (out) of Level 3	1,693		1,721
Ending balance	5,275	$ 1,316	5,275	$ 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		$ 2,528		$ 3,533
Total gains or (losses) (realized/unrealized), Included in earnings		1,235		1,291
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)		(284)		(191)
Purchases, issuances and settlements		17,898		16,744
Transfers in and/or (out) of Level 3		(1,101)		(1,101)
Ending balance		$ 20,276		$ 20,276
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]
Beginning balance			8,597
Transfers in and/or (out) of Level 3			(8,597)
Foreign Corporate Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	7,837		7,166	$ 481
Total gains or (losses) (realized/unrealized), Included in earnings	62		177	18
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	(1,287)	$ (50)	(1,216)	(70)
Purchases, issuances and settlements		3,614		3,135
Transfers in and/or (out) of Level 3	(487)		(2)
Ending balance	$ 6,125	$ 3,564	$ 6,125	$ 3,564
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		$ 4		$ 4
Total gains or (losses) (realized/unrealized), Included in earnings		2		3
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)		(3)		(3)
Purchases, issuances and settlements		$ (3)		$ (4)
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