CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Net premiums	$ 2,562,042	$ 2,489,797	$ 7,739,053	$ 7,335,944
Investment income, net of related expenses	572,742	556,918	1,617,132	1,589,820
Investment related gains (losses), net:
Other-than-temporary impairments on fixed maturity securities	(10,705)	(390)	(14,055)	(20,980)
Other investment related gains (losses), net	(9,312)	23,043	(17,004)	160,451
Total investment related gains (losses), net	(20,017)	22,653	(31,059)	139,471
Other revenues	112,764	75,942	272,020	218,091
Total revenues	3,227,531	3,145,310	9,597,146	9,283,326
Benefits and Expenses:
Claims and other policy benefits	2,209,920	2,100,680	6,851,614	6,371,188
Interest credited	143,292	126,099	333,068	349,068
Policy acquisition costs and other insurance expenses	310,639	365,424	987,817	1,064,645
Other operating expenses	200,262	168,417	586,495	481,279
Interest expense	33,290	36,836	107,769	108,590
Collateral finance and securitization expense	7,467	7,692	22,509	21,235
Total benefits and expenses	2,904,870	2,805,148	8,889,272	8,396,005
Income before income taxes	322,661	340,162	707,874	887,321
Provision for income taxes	21,462	112,571	102,071	282,028
Net income	$ 301,199	$ 227,591	$ 605,803	$ 605,293
Earnings per share:
Basic earnings per share	$ 4.76	$ 3.53	$ 9.47	$ 9.39
Diluted earnings per share	4.68	3.47	9.30	9.23
Dividends declared per share	$ 0.60	$ 0.50	$ 1.60	$ 1.32