Fair Value (Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs By Asset Type) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 16,302	$ 8,778	$ 5,526	$ 15,763
Total gains or (losses) (realized/unrealized), Included in earnings	(18)	60	(1,007)	119
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	1,398	1,166	1,392	69
Purchases, issuances and settlements	16,749	(12)	28,520	1,928
Transfers in and/or (out) of Level 3		(197)		(8,084)
Ending balance	34,431	9,795	34,431	9,795
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			(997)
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	15,706	2,653	3,933
Total gains or (losses) (realized/unrealized), Included in earnings	(18)	2	(10)	4
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	(27)	(3)	(33)	(2)
Purchases, issuances and settlements	16,749	(12)	28,520	1,928
Transfers in and/or (out) of Level 3		(682)		28
Ending balance	32,410	1,958	32,410	1,958
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 Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	596	6,125	1,593	7,166
Total gains or (losses) (realized/unrealized), Included in earnings		58	(997)	115
Total gains or (losses) (realized/unrealized), Included in other comprehensive income (loss)	1,425	1,169	1,425	71
Purchases, issuances and settlements
Transfers in and/or (out) of Level 3		485		485
Ending balance	$ 2,021	$ 7,837	2,021	$ 7,837
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			$ (997)