Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 segment	Sep. 30, 2013
Financial information of the segments
Number of reportable segments			3
Revenues
Premium income	$ 169,543	$ 137,401	$ 363,893	$ 382,080
Fee income	181,991	152,343	520,509	453,596
Other revenue	0	0	0	7,355
Net investment income	292,061	375,041	911,694	909,006
Realized investment gains (losses), net	23,530	(55,820)	87,495	(65,395)
Total revenues	667,125	608,965	1,883,591	1,686,642
Benefits and expenses:
Policyholder benefits	361,991	334,464	931,067	944,329
Operating expenses	214,843	169,243	601,995	540,401
Total benefits and expenses	576,834	503,707	1,533,062	1,484,730
Income (loss) before income taxes	90,291	105,258	350,529	201,912
Income tax expense	29,790	33,287	120,324	67,159
Net income	60,501	71,971	230,205	134,753
Individual Markets
Revenues
Premium income	151,831	120,489	302,070	303,073
Fee income	20,781	20,018	71,349	67,393
Other revenue				7,355
Net investment income	181,944	201,727	554,508	551,167
Realized investment gains (losses), net	9,458	(12,797)	26,182	3,957
Total revenues	364,014	329,437	954,109	932,945
Benefits and expenses:
Policyholder benefits	282,985	261,716	700,694	715,691
Operating expenses	46,463	33,768	123,892	107,178
Total benefits and expenses	329,448	295,484	824,586	822,869
Income (loss) before income taxes	34,566	33,953	129,523	110,076
Income tax expense	11,598	10,716	44,516	38,349
Net income	22,968	23,237	85,007	71,727
Retirement Services
Revenues
Premium income	173	1,484	1,213	2,669
Fee income	160,241	131,103	446,201	382,809
Other revenue				0
Net investment income	96,771	159,547	316,724	320,179
Realized investment gains (losses), net	13,777	(43,023)	60,933	(69,365)
Total revenues	270,962	249,111	825,071	636,292
Benefits and expenses:
Policyholder benefits	51,396	53,201	151,397	146,562
Operating expenses	153,970	123,810	433,529	385,039
Total benefits and expenses	205,366	177,011	584,926	531,601
Income (loss) before income taxes	65,596	72,100	240,145	104,691
Income tax expense	21,912	22,866	82,271	33,509
Net income	43,684	49,234	157,874	71,182
Other
Revenues
Premium income	17,539	15,428	60,610	76,338
Fee income	969	1,222	2,959	3,394
Other revenue				0
Net investment income	13,346	13,767	40,462	37,660
Realized investment gains (losses), net	295	0	380	13
Total revenues	32,149	30,417	104,411	117,405
Benefits and expenses:
Policyholder benefits	27,610	19,547	78,976	82,076
Operating expenses	14,410	11,665	44,574	48,184
Total benefits and expenses	42,020	31,212	123,550	130,260
Income (loss) before income taxes	(9,871)	(795)	(19,139)	(12,855)
Income tax expense	(3,720)	(295)	(6,463)	(4,699)
Net income	$ (6,151)	$ (500)	$ (12,676)	$ (8,156)