Fair Value of Financial Instruments (Assets Measured on Recurring Basis Utilizing Level 3 Inputs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value Disclosures [Abstract]
fair value,measurement with unobservable inputs reconciliation,changes in unrealized gains included in earnings related to assets still held at period end					$ (1,975)	$ 396
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	4,380,094	3,724,103	3,888,542	3,504,623	3,888,542	3,504,623
Net realized gains/(losses)	400	(228)	(1,482)	1,571
Net unrealized (losses)/gains	(1,889)	(2,326)	86	(2,722)
Purchases	41,355	36,116	96,760	180,124
Sales	(544,322)	(64,356)	(195,559)	(90,024)
Issuances	692	214	1,292	0
Settlements	0	0	0	(1,195)
Transfers into Level 3			593,325	13,357	762,849
Transfers (out of) Level 3	(96,371)	(9,632)	(132,270)	(5,370)		(13,353)
Transfers into Level 3	169,524	0
Attributable to policyowner	105,665	61,960	126,608	121,437
Balance at end of period	$ 4,055,148	$ 3,745,851	$ 4,380,094	$ 3,724,103	$ 4,055,148	$ 3,745,851