Fair Value Disclosures (Change In Balance Sheet Carrying Value Associated With Level 3 Financial Assets Carried At Fair Value) (Details) - Level 3 - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, net		$ 40,576	$ 89,018
Total (losses) gains (realized/unrealized) included in earnings, net	[1]	2,342	(2,197)
Net unrealized gains (losses) included in other comprehensive income	[2]	(1,613)	(3,527)
Purchases, net		66,725	16,321
Sales, net		(10,534)	(7,556)
Transfers into Level 3, net	[3]	21,130	30,538
Transfers out of Level 3, net	[3]	(30,449)	(82,021)
Balance, end of period, net		88,177	40,576
Other liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, liabilities		(27,683)	(25,233)
Total (losses) gains (realized/unrealized) included in earnings, liabilities	[1]	4,919	(2,450)
Net unrealized (losses) gains included in other comprehensive income, liabilities	[2]	0	0
Purchases, liabilities		(687)	77
Sales, liabilities		0	(77)
Transfers into Level 3, liabilities	[3]	0	0
Transfers out of Level 3, liabilities	[3]	0	0
Balance, end of period, liabilities		(23,451)	(27,683)
State, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		0
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	0
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	0
Purchases, assets		3,600
Sales, assets		(3,600)
Transfers into Level 3, assets	[3]	0
Transfers out of Level 3, assets	[3]	0
Balance, end of period, assets		0	0
Commercial mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		204	403
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	(2,071)	0
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(992)	(11)
Purchases, assets		30,822	0
Sales, assets		(201)	(188)
Transfers into Level 3, assets	[3]	0	0
Transfers out of Level 3, assets	[3]	0	0
Balance, end of period, assets		27,762	204
Residential mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		0	4,645
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]		1
Net unrealized (losses) gains included in other comprehensive income, assets	[2]		(104)
Purchases, assets			9,721
Sales, assets			0
Transfers into Level 3, assets	[3]		0
Transfers out of Level 3, assets	[3]		(14,263)
Balance, end of period, assets			0
U.S. corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		34,504	100,133
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	469	(115)
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(99)	(992)
Purchases, assets		28,949	6,523
Sales, assets		(5,134)	(5,417)
Transfers into Level 3, assets	[3]	16,311	2,130
Transfers out of Level 3, assets	[3]	(30,449)	(67,758)
Balance, end of period, assets		44,551	34,504
Foreign corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		28,642	4,142
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	90	706
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(415)	(2,628)
Purchases, assets		1,685	0
Sales, assets		(1,510)	(1,750)
Transfers into Level 3, assets	[3]	4,819	28,172
Transfers out of Level 3, assets	[3]	0	0
Balance, end of period, assets		33,311	28,642
Non-redeemable preferred stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		2,250	2,000
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	0	0
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(62)	250
Purchases, assets		0	0
Sales, assets		0	0
Transfers into Level 3, assets	[3]	0	0
Transfers out of Level 3, assets	[3]	0	0
Balance, end of period, assets		2,188	2,250
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		2,225	2,121
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	(981)	34
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(45)	(42)
Purchases, assets		2,356	0
Sales, assets		(89)	(124)
Transfers into Level 3, assets	[3]	0	236
Transfers out of Level 3, assets	[3]	0	0
Balance, end of period, assets		3,466	2,225
Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period, assets		434	807
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	(84)	(373)
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	0	0
Purchases, assets		0	0
Sales, assets		0	0
Transfers into Level 3, assets	[3]	0	0
Transfers out of Level 3, assets	[3]	0	0
Balance, end of period, assets		$ 350	$ 434

[1] Included as part of net realized gains on investments in the consolidated statement of operations.

[2] Included as part of change in unrealized gains on securities in the consolidated statement of comprehensive income.

[3] Transfers are primarily attributable to changes in the availability of observable market information and re-evaluation of the observability of pricing inputs.