Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)
Financial information of the segments
Number of reportable segments | segment			3
Revenues
Premium income	$ 146,100	$ 154,017	$ 377,845	$ 374,437
Fee income	246,413	225,242	709,844	688,020
Other revenue	3,228	1,820	9,747	5,460
Net investment income	291,539	363,057	979,080	942,082
Realized investment gains (losses), net	33,374	22,551	106,657	56,610
Total revenues	720,654	766,687	2,183,173	2,066,609
Benefits and expenses:
Policyholder benefits	346,861	357,614	946,876	957,603
Operating expenses	318,481	310,792	944,815	870,908
Total benefits and expenses	665,342	668,406	1,891,691	1,828,511
Income before income taxes	55,312	98,281	291,482	238,098
Income tax expense	15,295	30,708	79,043	78,926
Net income	40,017	67,573	212,439	159,172
Operating Segments | Individual Markets
Revenues
Premium income	126,770	132,761	311,110	308,976
Fee income	23,553	19,745	71,823	66,214
Other revenue	0	0	0	0
Net investment income	185,747	222,445	619,633	595,757
Realized investment gains (losses), net	11,026	8,304	37,602	20,256
Total revenues	347,096	383,255	1,040,168	991,203
Benefits and expenses:
Policyholder benefits	280,821	270,614	749,790	725,526
Operating expenses	35,948	49,407	127,181	116,770
Total benefits and expenses	316,769	320,021	876,971	842,296
Income before income taxes	30,327	63,234	163,197	148,907
Income tax expense	10,102	21,539	55,183	51,262
Net income	20,225	41,695	108,014	97,645
Operating Segments | Empower Retirement
Revenues
Premium income	605	477	1,311	493
Fee income	221,342	204,488	633,679	618,841
Other revenue	3,228	1,820	9,747	5,460
Net investment income	94,383	127,160	321,972	305,969
Realized investment gains (losses), net	21,565	14,247	68,278	36,257
Total revenues	341,123	348,192	1,034,987	967,020
Benefits and expenses:
Policyholder benefits	51,730	54,401	153,587	151,194
Operating expenses	263,327	242,841	761,827	704,047
Total benefits and expenses	315,057	297,242	915,414	855,241
Income before income taxes	26,066	50,950	119,573	111,779
Income tax expense	5,442	14,884	20,579	35,651
Net income	20,624	36,066	98,994	76,128
Operating Segments | Other
Revenues
Premium income	18,725	20,779	65,424	64,968
Fee income	1,518	1,009	4,342	2,965
Other revenue	0	0	0	0
Net investment income	11,409	13,452	37,475	40,356
Realized investment gains (losses), net	783	0	777	97
Total revenues	32,435	35,240	108,018	108,386
Benefits and expenses:
Policyholder benefits	14,310	32,599	43,499	80,883
Operating expenses	19,206	18,544	55,807	50,091
Total benefits and expenses	33,516	51,143	99,306	130,974
Income before income taxes	(1,081)	(15,903)	8,712	(22,588)
Income tax expense	(249)	(5,715)	3,281	(7,987)
Net income	$ (832)	$ (10,188)	$ 5,431	$ (14,601)