Fair Value Level 3 Financial Instruments changes in Fair Value recurring basis (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, 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]
Asset Balance at beginning of period	$ 212,739	$ 275,390
Asset Purchases	84,972	105,848
Asset Sales	(30,750)	(33,809)
Asset, Gain (Loss) Included in Earnings	(27)	0
Gain/Loss in Other Comprehensive Income (Loss)	(22)	(5,157)
Asset Transfers Into Level 3	68,447	57,634
Asset, Transfers out of Level 3	(133,188)	(187,965)
Asset, Amortization	161	798
Asset Balance at end of period	202,332	212,739
Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	49,076	64,239
Asset Purchases	2,000	15,993
Asset Sales	(13,751)	(20,499)
Asset, Gain (Loss) Included in Earnings	(27)	0
Gain/Loss in Other Comprehensive Income (Loss)	(490)	(55)
Asset Transfers Into Level 3	35,956	21,363
Asset, Transfers out of Level 3	(13,572)	(32,649)
Asset, Amortization	(73)	574
Asset Balance at end of period	59,119	49,076
Residential mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	3,729	0
Asset Purchases	0	19,353
Asset Sales	(3,722)	(2,340)
Asset, Gain (Loss) Included in Earnings	0	0
Gain/Loss in Other Comprehensive Income (Loss)	(137)	284
Asset Transfers Into Level 3	0	5,984
Asset, Transfers out of Level 3	0	(19,631)
Asset, Amortization	130	79
Asset Balance at end of period	0	3,729
Commercial mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	88,180	77,891
Asset Purchases	18,826	17,287
Asset Sales	(1,656)	(885)
Asset, Gain (Loss) Included in Earnings	0	0
Gain/Loss in Other Comprehensive Income (Loss)	(141)	3,905
Asset Transfers Into Level 3	0	0
Asset, Transfers out of Level 3	(23,852)	(2,334)
Asset, Amortization	77	126
Asset Balance at end of period	81,434	88,180
Other asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	55,557	116,141
Asset Purchases	64,146	53,215
Asset Sales	(11,621)	(10,085)
Asset, Gain (Loss) Included in Earnings	0	0
Gain/Loss in Other Comprehensive Income (Loss)	212	662
Asset Transfers Into Level 3	30,098	30,287
Asset, Transfers out of Level 3	(84,045)	(133,351)
Asset, Amortization	21	12
Asset Balance at end of period	54,368	55,557
United States Government and agencies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	8,726	9,065
Asset Purchases	0	0
Asset Sales	0	0
Asset, Gain (Loss) Included in Earnings	0	0
Gain/Loss in Other Comprehensive Income (Loss)	486	346
Asset Transfers Into Level 3	0	0
Asset, Transfers out of Level 3	(9,218)	0
Asset, Amortization	6	7
Asset Balance at end of period	0	8,726
State, municipal and other governments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	0
Asset Purchases	0
Asset Sales	0
Asset, Gain (Loss) Included in Earnings	0
Gain/Loss in Other Comprehensive Income (Loss)	108
Asset Transfers Into Level 3	2,393
Asset, Transfers out of Level 3	(2,501)
Asset, Amortization	0
Asset Balance at end of period	0	0
Non-redeemable preferred stocks
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Asset Balance at beginning of period	7,471	8,054
Asset Purchases	0	0
Asset Sales	0	0
Asset, Gain (Loss) Included in Earnings	0	0
Gain/Loss in Other Comprehensive Income (Loss)	(60)	(583)
Asset Transfers Into Level 3	0	0
Asset, Transfers out of Level 3	0	0
Asset, Amortization	0	0
Asset Balance at end of period	7,411	7,471
Index Annuity Embedded Derivatives [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liability Value beginning of period	9,374	8,681
Liability, Purchases	5,913	4,567
Liability, Settlements	(115)	(1,064)
Liability, Gain (Loss) Included in Earnings	606	2,810
Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Liability, Transfers Into Level 3	0	0
Liability, Transfers out of Level 3	0	0
Liability Value end of period	$ 15,778	$ 9,374