Derivative Instruments (Financial Statement Classification and Impact of Derivatives Used in Qualifying and Non-qualifying Hedge Relationships) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net	$ 8,640		$ (680)		$ (2,207)
Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(8,113)		(194,055)		(107,663)
Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	14		(89)		(116)
Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	277		17		(3)
Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,492	[1]	(585)	[1]	(2,106)	[1]
Cash Flow Hedging [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Cash Flow Hedging [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	14		(89)		(116)
Cash Flow Hedging [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	134		(7)		14
Cash Flow Hedging [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,492	[1]	(585)	[1]	(2,106)	[1]
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	14		(89)		(116)
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	134		(7)		14
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,492	[1]	(585)	[1]	(2,106)	[1]
Nondesignated [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(8,113)		(194,055)		(107,663)
Nondesignated [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	143		24		(17)
Nondesignated [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]	0	[1]
Nondesignated [Member] | Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	123,327		(116,025)		5,030
Nondesignated [Member] | Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]	0	[1]
Nondesignated [Member] | Foreign Exchange Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net					(15)
Nondesignated [Member] | Foreign Exchange Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net					0
Nondesignated [Member] | Foreign Exchange Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net					0
Nondesignated [Member] | Foreign Exchange Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net					0	[1]
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	5,934		(204)		(1,368)
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	143		24		(17)
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]	0	[1]
Nondesignated [Member] | Credit Risk Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(14)		(103)		143
Nondesignated [Member] | Credit Risk Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Credit Risk Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Credit Risk Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]	0	[1]
Nondesignated [Member] | Equity Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(23,811)		(79,498)		(56,158)
Nondesignated [Member] | Equity Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Equity Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Equity Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]	0	[1]
Nondesignated [Member] | Embedded Derivative [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(113,549)		1,775		(55,295)
Nondesignated [Member] | Embedded Derivative [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Embedded Derivative [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0		0
Nondesignated [Member] | Embedded Derivative [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 0	[1]	$ 0	[1]	$ 0	[1]

[1] (1) Amounts deferred in “Accumulated other comprehensive income (loss).”