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	$ 24,952	$ 0
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	24,952	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(3,386)
Restricted stock units expensed			23,387
Net income before noncontrolling interests	$ 68,130			66,842					1,288
Dividends ( $0.63, $0.12, $0.75 and $0.23 per share, respectively)				(41,420)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	59,743					34,753
Change in unrealized (losses) gains on securities with an allowance for expected credit losses						24,991
Net change in period	(76,747)						(76,747)
Stock exercised/vested								2,221
Stock repurchased								(298,902)
Distributions									(417)
Other comprehensive income (loss), net of tax	(17,004)				(17,004)		(76,747)		1
End of period at Jun. 30, 2020			1,076,043	7,927,280	(249,350)	209,210	(458,560)	(3,023,392)	44,275
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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	0		0
Beginning of period at Mar. 31, 2020		70,535	1,063,084	7,877,371	(589,521)	(109,514)	(480,007)	(2,927,994)	44,069	0		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			1,204
Restricted stock units expensed			11,755
Net income before noncontrolling interests	71,656			71,260					396
Dividends ( $0.63, $0.12, $0.75 and $0.23 per share, respectively)				(21,351)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	318,725					295,274
Change in unrealized (losses) gains on securities with an allowance for expected credit losses						23,450
Net change in period	21,447						21,447
Stock exercised/vested								883
Stock repurchased								(96,281)
Distributions									(189)
Other comprehensive income (loss), net of tax	$ 340,172				340,172		21,447		(1)
End of period at Jun. 30, 2020			1,076,043	7,927,280	(249,350)	209,210	(458,560)	(3,023,392)	44,275
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.23
Cumulative effect adjustment resulting from changes in accounting principles			1,076,043	7,927,280	(249,350)	209,210	(458,560)	(3,023,392)	44,275
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		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		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			72
Restricted stock units expensed			22,611
Net income before noncontrolling interests	469,394			466,763					2,631
Dividends ( $0.63, $0.12, $0.75 and $0.23 per share, respectively)				(133,056)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	(66,858)					(77,145)
Change in unrealized (losses) gains on securities with an allowance for expected credit losses						10,286
Net change in period	6,587						6,587
Stock exercised/vested								1,039
Stock repurchased								(29,683)
Distributions									(7,947)
Other comprehensive income (loss), net of tax	(60,271)				(60,271)		6,587		(1)
End of period at Jun. 30, 2021	6,587,954		1,035,166	8,682,088	(122,444)	222,855	(345,299)	(3,087,069)	9,678
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment resulting from changes in accounting principles		70,535	1,023,556	8,556,621	(148,252)	199,584	(347,836)	(3,087,860)	15,684	0		0
Beginning of period at Mar. 31, 2021		$ 70,535	1,023,556	8,556,621	(148,252)	199,584	(347,836)	(3,087,860)	15,684	$ 0		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			597
Restricted stock units expensed			11,013
Net income before noncontrolling interests	237,678			237,238					440
Dividends ( $0.63, $0.12, $0.75 and $0.23 per share, respectively)				(111,771)
Change in unrealized gains (losses) on securities without an allowance for expected credit losses	23,272					23,340
Change in unrealized (losses) gains on securities with an allowance for expected credit losses						(69)
Net change in period	2,537						2,537
Stock exercised/vested								791
Stock repurchased								0
Distributions									(6,445)
Other comprehensive income (loss), net of tax	25,809				25,809		2,537		(1)
End of period at Jun. 30, 2021	$ 6,587,954		1,035,166	8,682,088	(122,444)	222,855	(345,299)	(3,087,069)	9,678
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	$ 6,587,954		$ 1,035,166	$ 8,682,088	$ (122,444)	$ 222,855	$ (345,299)	$ (3,087,069)	$ 9,678