Investments (Fixed Maturities and Equity Securities Excluding Investments Classified as Trading) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	$ 2,644,828,000		$ 3,079,002,000
Available-for-sale equity securities amortized cost basis	14,000		206,000
Fair Value, Fixed maturities, available for sale	2,840,070,000		3,264,216,000
Equity securities, available for sale	17,000		208,000
Net unrealized gains on impaired securities relating to changes in value of securities subsequent to the impairment measurement date	100,000		1,700,000
Fixed Maturities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	2,644,828,000		3,079,002,000
Gross Unrealized Gains	201,291,000		207,110,000
Gross Unrealized Losses	6,049,000		21,896,000
Fair Value, Fixed maturities, available for sale	2,840,070,000		3,264,216,000
Other-than-temporary impairments in AOCI	77,000	[1]	1,391,000	[2]
Fixed Maturities [Member] | US Treasury And Government [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	6,331,000		6,382,000
Gross Unrealized Gains	0		36,000
Gross Unrealized Losses	22,000		34,000
Fair Value, Fixed maturities, available for sale	6,309,000		6,384,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Obligations of U.S. states and their political subdivisions [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	69,058,000		67,225,000
Gross Unrealized Gains	1,651,000		2,911,000
Gross Unrealized Losses	403,000		1,570,000
Fair Value, Fixed maturities, available for sale	70,306,000		68,566,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Foreign Government Debt Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	25,130,000		25,437,000
Gross Unrealized Gains	6,941,000		5,717,000
Gross Unrealized Losses	0		0
Fair Value, Fixed maturities, available for sale	32,071,000		31,154,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Public Utilities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	193,968,000		229,807,000
Gross Unrealized Gains	16,641,000		17,048,000
Gross Unrealized Losses	1,455,000		3,190,000
Fair Value, Fixed maturities, available for sale	209,154,000		243,665,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Corporate Debt Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	1,767,282,000		2,029,720,000
Gross Unrealized Gains	155,548,000		158,360,000
Gross Unrealized Losses	3,659,000		9,103,000
Fair Value, Fixed maturities, available for sale	1,919,171,000		2,178,977,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Asset-backed Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	145,579,000	[3]	182,888,000	[3]
Gross Unrealized Gains	5,736,000	[3]	6,513,000	[3]
Gross Unrealized Losses	185,000	[3]	1,509,000	[3]
Fair Value, Fixed maturities, available for sale	151,130,000	[3]	187,892,000	[3]
Other-than-temporary impairments in AOCI	40,000	[1],[3]	1,351,000	[2],[3]
Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	305,077,000		384,764,000
Gross Unrealized Gains	8,641,000		11,387,000
Gross Unrealized Losses	325,000		5,518,000
Fair Value, Fixed maturities, available for sale	313,393,000		390,633,000
Other-than-temporary impairments in AOCI	0	[1]	0	[2]
Fixed Maturities [Member] | Residential Mortgage Backed Securities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Fixed maturities, available-for-sale, amortized cost	132,403,000	[4]	152,779,000	[4]
Gross Unrealized Gains	6,133,000	[4]	5,138,000	[4]
Gross Unrealized Losses	0	[4]	972,000	[4]
Fair Value, Fixed maturities, available for sale	138,536,000	[4]	156,945,000	[4]
Other-than-temporary impairments in AOCI	37,000	[1],[4]	40,000	[2],[4]
Equity Securities Available For Sale [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Available-for-sale equity securities amortized cost basis	14,000		206,000
Gross Unrealized Gains	3,000		2,000
Gross Unrealized Losses	0		0
Equity securities, available for sale	17,000		208,000
Equity Securities Available For Sale [Member] | Public Utilities [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Available-for-sale equity securities amortized cost basis	0		192,000
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Equity securities, available for sale	0		192,000
Equity Securities Available For Sale [Member] | Mutual Fund [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Available-for-sale equity securities amortized cost basis	14,000		14,000
Gross Unrealized Gains	3,000		2,000
Gross Unrealized Losses	0		0
Equity securities, available for sale	$ 17,000		$ 16,000

[1] Represents the amount of other-than-temporary impairment losses in AOCI, which were not included in earnings. Amount excludes $0.1 million of net unrealized gains on impaired available-for-sale securities relating to changes in the value of such securities subsequent to the impairment measurement date.

[2] Represents the amount of other-than-temporary impairment losses in AOCI, which were not included in earnings. Amount excludes $1.7 million of net unrealized gains on impaired available-for-sale securities relating to changes in the value of such securities subsequent to the impairment measurement date.

[3] _____________ Includes credit-tranched securities collateralized by sub-prime mortgages, auto loans, credit cards, education loans, and other asset types.

[4] Includes publicly-traded agency pass-through securities and collateralized mortgage obligations.