Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)
Financial information of the segments
Number of reportable segments | segment			3
Revenues
Premium income	$ 67,663	$ 76,818	$ 219,904	$ 231,745
Fee income	267,338	238,364	522,453	463,429
Other revenue	3,661	3,370	6,045	6,519
Net investment income	297,221	355,755	610,691	687,540
Realized investment gains (losses), net	22,064	42,013	10,310	73,283
Total revenues	657,947	716,320	1,369,403	1,462,516
Benefits and expenses:
Policyholder benefits	269,544	263,271	608,971	600,015
Operating expenses	312,411	339,540	632,494	626,332
Total benefits and expenses	581,955	602,811	1,241,465	1,226,347
Income before income taxes	75,992	113,509	127,938	236,169
Income tax expense	26,168	39,710	43,286	63,748
Net income	49,824	73,799	84,652	172,421
Individual Markets
Revenues
Premium income	44,701	51,053
Fee income	29,199	25,546
Other revenue	0	0
Net investment income	192,788	226,193
Realized investment gains (losses), net	4,037	14,771
Total revenues	270,725	317,563
Benefits and expenses:
Policyholder benefits	198,171	201,472
Operating expenses	47,420	54,010
Total benefits and expenses	245,591	255,482
Income before income taxes	25,134	62,081
Income tax expense	8,531	21,247
Net income	16,603	40,834
Empower Retirement
Revenues
Premium income	1,052	362
Fee income	236,573	211,414
Other revenue	3,661	3,370
Net investment income	92,756	117,055
Realized investment gains (losses), net	18,011	27,242
Total revenues	352,053	359,443
Benefits and expenses:
Policyholder benefits	50,702	51,939
Operating expenses	249,178	266,857
Total benefits and expenses	299,880	318,796
Income before income taxes	52,173	40,647
Income tax expense	17,996	14,486
Net income	34,177	26,161
Other
Revenues
Premium income	21,910	25,403
Fee income	1,566	1,404
Other revenue	0	0
Net investment income	11,677	12,507
Realized investment gains (losses), net	16	0
Total revenues	35,169	39,314
Benefits and expenses:
Policyholder benefits	20,671	9,860
Operating expenses	15,813	18,673
Total benefits and expenses	36,484	28,533
Income before income taxes	(1,315)	10,781
Income tax expense	(359)	3,977
Net income	$ (956)	$ 6,804
Operating Segments | Individual Markets
Revenues
Premium income			176,260	184,339
Fee income			55,180	48,269
Other revenue			0	0
Net investment income			376,993	433,886
Realized investment gains (losses), net			4,622	26,577
Total revenues			613,055	693,071
Benefits and expenses:
Policyholder benefits			468,259	468,969
Operating expenses			85,807	91,231
Total benefits and expenses			554,066	560,200
Income before income taxes			58,989	132,871
Income tax expense			20,182	45,081
Net income			38,807	87,790
Operating Segments | Empower Retirement
Revenues
Premium income			1,143	707
Fee income			463,892	412,336
Other revenue			6,045	6,519
Net investment income			210,375	227,589
Realized investment gains (losses), net			5,695	46,713
Total revenues			687,150	693,864
Benefits and expenses:
Policyholder benefits			98,330	101,856
Operating expenses			504,941	498,500
Total benefits and expenses			603,271	600,356
Income before income taxes			83,879	93,508
Income tax expense			28,421	15,137
Net income			55,458	78,371
Operating Segments | Other
Revenues
Premium income			42,501	46,699
Fee income			3,381	2,824
Other revenue			0	0
Net investment income			23,323	26,065
Realized investment gains (losses), net			(7)	(7)
Total revenues			69,198	75,581
Benefits and expenses:
Policyholder benefits			42,382	29,190
Operating expenses			41,746	36,601
Total benefits and expenses			84,128	65,791
Income before income taxes			(14,930)	9,790
Income tax expense			(5,317)	3,530
Net income			$ (9,613)	$ 6,260