Fair Value Disclosures (Change in Balance Sheet Carrying Value Associated with Level 3 Financial Assets and Liabilities Carried at Fair Value) (Details) - Level 3 - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Total Level 3 Assets and Liabilities
Balance, beginning of period, net		$ 40,576	$ 89,018
Total (losses) gains (realized/unrealized) included in earnings, net	[1]	(473)	(691)
Net unrealized (losses) gains included in other comprehensive income	[2]	149	933
Purchases, net		8,100
Sales, net		(794)	(2,222)
Transfers in, net	[3]		2,366
Transfers out, net	[3]	(4,831)	(8,777)
Balance, end of period, net		42,727	80,627
Other liabilities
Financial Liabilities
Balance, beginning of period, liabilities		(27,683)	(25,233)
Total (losses) gains (realized/unrealized) including earnings, liabilities	[1]	91	(948)
Net unrealized (losses) gains included in other comprehensive income, liabilities	[2]	0	0
Purchases, liabilities		0
Sales, liabilities		0	0
Transfers in, liabilities	[3]		0
Transfers out, liabilities	[3]	0	0
Balance, end of period, liabilities		(27,592)	(26,181)
Commercial mortgage-backed
Financial Assets
Balance, beginning of period, assets		204	403
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	0	0
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(1)	(3)
Purchases, assets		0
Sales, assets		(49)	(46)
Transfers in, assets	[3]		0
Transfers out, assets	[3]	0	0
Balance, end of period, assets		154	354
Residential mortgage-backed
Financial Assets
Balance, beginning of period, assets			4,645
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]		0
Net unrealized (losses) gains included in other comprehensive income, assets	[2]		0
Sales, assets			0
Transfers in, assets	[3]		0
Transfers out, assets	[3]		(4,645)
Balance, end of period, assets			0
Corporate
Financial Assets
Balance, beginning of period, assets		63,146	104,275
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	145	(8)
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	51	880
Purchases, assets		8,100
Sales, assets		(719)	(2,155)
Transfers in, assets	[3]		2,130
Transfers out, assets	[3]	(4,831)	(4,132)
Balance, end of period, assets		65,892	100,990
Non-redeemable preferred stocks
Financial Assets
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]	110	60
Purchases, assets		0
Sales, assets		0	0
Transfers in, assets	[3]		0
Transfers out, assets	[3]	0	0
Balance, end of period, assets		2,360	2,060
Other investments
Financial Assets
Balance, beginning of period, assets		2,225	2,121
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	(636)	128
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	(11)	(4)
Purchases, assets		0
Sales, assets		(26)	(21)
Transfers in, assets	[3]		236
Transfers out, assets	[3]	0	0
Balance, end of period, assets		1,552	2,460
Other assets
Financial Assets
Balance, beginning of period, assets		434	807
Total (losses) gains (realized/unrealized) included in earnings, assets	[1]	(73)	137
Net unrealized (losses) gains included in other comprehensive income, assets	[2]	0	0
Purchases, assets		0
Sales, assets		0	0
Transfers in, assets	[3]		0
Transfers out, assets	[3]	0	0
Balance, end of period, assets		$ 361	$ 944

[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.