CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 177,043	$ 103,514	$ 285,828	$ 176,719
Other comprehensive income (loss), net of tax:
Unrealized investment gains (losses) arising during the period	131,442	(105,280)	321,651	(217,434)
Adjustment for reclassification of net realized investment (gains) losses and OTTI losses recognized in net income	(6,949)	36,456	6,385	37,240
Unrealized investment gains (losses) arising during the period, net of reclassification adjustment	124,493	(68,824)	328,036	(180,194)
Foreign currency translation adjustment	2,556	(9,129)	5,219	(7,858)
Total other comprehensive income (loss), net of tax	127,049	(77,953)	333,255	(188,052)
Comprehensive income (loss)	$ 304,092	$ 25,561	$ 619,083	$ (11,333)