CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums	$ 10,543,776	$ 9,841,130	$ 9,248,871
Investment income, net of related expenses	2,138,525	2,154,651	1,911,886
Investment related gains (losses), net:
Other-than-temporary impairments on fixed maturity securities	(28,494)	(42,639)	(38,805)
Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income	0	0	74
Other investment related gains (losses), net	(141,594)	210,519	132,926
Total investment related gains (losses), net	(170,088)	167,880	94,195
Other revenues	363,451	352,108	266,559
Total revenues	12,875,664	12,515,769	11,521,511
Benefits and expenses
Claims and other policy benefits	9,318,929	8,518,917	7,993,375
Interest credited	425,204	502,040	364,691
Policy acquisition costs and other insurance expenses	1,322,520	1,466,646	1,310,540
Other operating expenses	786,137	710,690	645,509
Interest expense	147,355	146,025	137,623
Collateral finance and securitization expense	29,699	28,636	25,827
Total benefits and expenses	12,029,844	11,372,954	10,477,565
Income before income taxes	845,820	1,142,815	1,043,946
Provision for income taxes	129,978	(679,366)	342,503
Net income	$ 715,842	$ 1,822,181	$ 701,443
Earnings per share
Basic earnings per share (in dollars per share)	$ 11.25	$ 28.28	$ 10.91
Diluted earnings per share (in dollars per share)	$ 11.00	$ 27.71	$ 10.79