Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated Other Comprehensive Income (Loss)	Unrealized investment gain	Currency Translation Adjustments	Treasury stock	Noncontrolling interest	Cumulative effect adjustment resulting from changes in accounting principles Retained earnings	Cumulative effect adjustment resulting from changes in accounting principles Accumulated Other Comprehensive Income (Loss)	Cumulative effect adjustment resulting from changes in accounting principles Unrealized investment gain	Cumulative effect adjustment resulting from changes in accounting principles Currency Translation Adjustments
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles		$ 70,535	$ 1,056,042	$ 7,932,372	$ (257,299)	$ 124,514	$ (381,813)	$ (2,726,711)	$ 43,403	$ (30,514)		$ 24,952
Beginning of period at Dec. 31, 2019		70,535	1,056,042	7,932,372	(257,299)	124,514	(381,813)	(2,726,711)	43,403	(30,514)		24,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(4,590)
Restricted stock units expensed			11,632
Cumulative effect adjustment resulting from changes in accounting principles		70,535	1,063,084	7,877,371	(589,521)	(109,514)	(480,007)	(2,927,994)	44,069	(30,514)		24,952
Net income (loss) before noncontrolling interests	$ (3,526)			(4,418)					892
Dividends ($0.12 and $0.11 per share, respectively)				(20,069)
Change in unrealized gains on securities without an allowance for expected credit losses	(258,981)					(260,521)
Change in unrealized gains on securities with an allowance for expected credit losses						1,541
Net change in period	(98,194)						(98,194)
Stock exercised/vested								1,338
Stock repurchased								(202,621)
Distributions									(227)
Other comprehensive income, net of tax	$ (357,175)				(357,175)		(98,194)		1
End of period at Mar. 31, 2020			1,063,084	7,877,371	(589,521)	(109,514)	(480,007)	(2,927,994)	44,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.11
Cumulative effect adjustment resulting from changes in accounting principles			1,063,084	7,877,371	(589,521)	(109,514)	(480,007)	(2,927,994)	44,069
Cumulative effect adjustment resulting from changes in accounting principles	$ 6,325,797	70,535	1,012,483	8,348,381	(62,172)	289,714	(351,886)	(3,058,425)	14,995	0	$ 24,952	0	$ 0
Beginning of period at Dec. 31, 2020	6,325,797	70,535	1,012,483	8,348,381	(62,172)	289,714	(351,886)	(3,058,425)	14,995	0	24,952	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(525)
Restricted stock units expensed			11,598
Cumulative effect adjustment resulting from changes in accounting principles	6,325,797	$ 70,535	1,023,556	8,556,621	(62,172)	199,584	(351,886)	(3,087,860)	15,684	$ 0	$ 24,952	$ 0	$ 0
Net income (loss) before noncontrolling interests	231,716			229,525					2,191
Dividends ($0.12 and $0.11 per share, respectively)				(21,285)
Change in unrealized gains on securities without an allowance for expected credit losses	(90,130)					(100,485)
Change in unrealized gains on securities with an allowance for expected credit losses						10,355
Net change in period	4,050						4,050
Stock exercised/vested								248
Stock repurchased								(29,683)
Distributions									(1,502)
Other comprehensive income, net of tax	(86,080)				(86,080)		4,050		0
End of period at Mar. 31, 2021	$ 6,430,284		1,023,556	8,556,621	(148,252)	199,584	(347,836)	(3,087,860)	15,684
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.12
Cumulative effect adjustment resulting from changes in accounting principles	$ 6,430,284		$ 1,023,556	$ 8,556,621	$ (148,252)	$ 199,584	$ (347,836)	$ (3,087,860)	$ 15,684