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	$ 1,039,633	$ 7,558,619	$ (510,470)	$ (91,491)	$ (418,979)	$ (2,720,466)	$ 41,947	$ 0		$ 0
Beginning of period at Dec. 31, 2018		70,535	1,039,633	7,558,619	(510,470)	(91,491)	(418,979)	(2,720,466)	41,947	0		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock units issued			(455)
Restricted stock units expensed			14,194
Cumulative effect adjustment resulting from changes in accounting principles		70,535	1,053,372	7,721,039	(510,470)	34,236	(399,219)	(2,720,011)	42,844	0		0
Net (loss) income before noncontrolling interests	$ 181,614			180,722					892
Dividends ($0.11 and $0.10 per share, respectively)				(18,302)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	125,774					125,796
Change in unrealized gains (losses) on securities with an allowance for expected credit losses						(69)
Net change in period	19,760						19,760
Stock exercised/vested								455
Stock repurchased								0
(Distributions) contributions									52
Other comprehensive income (loss), net of tax	$ 145,534				145,534		19,760		(47)
End of period at Mar. 31, 2019			1,053,372	7,721,039	(364,983)	34,236	(399,219)	(2,720,011)	42,844
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends, per share, cash paid (in dollars per share)	$ 0.10
Cumulative effect adjustment resulting from changes in accounting principles			1,053,372	7,721,039	(364,983)	34,236	(399,219)	(2,720,011)	42,844
Cumulative effect adjustment resulting from changes in accounting principles	$ 6,118,342	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	6,118,342	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			(4,590)
Restricted stock units expensed			11,632
Cumulative effect adjustment resulting from changes in accounting principles	6,118,342	$ 70,535	1,063,084	7,877,371	(589,521)	(109,514)	(480,007)	(2,927,994)	44,069	$ (30,514)	$ 24,952	$ 24,952	$ 0
Net (loss) income before noncontrolling interests	(3,526)			(4,418)					892
Dividends ($0.11 and $0.10 per share, respectively)				(20,069)
Change in unrealized (losses) gains on securities without an allowance for expected credit losses	(258,981)					(260,521)
Change in unrealized gains (losses) 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) contributions									(227)
Other comprehensive income (loss), net of tax	(357,175)				(357,175)		(98,194)		1
End of period at Mar. 31, 2020	$ 5,537,544		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	$ 5,537,544		$ 1,063,084	$ 7,877,371	$ (589,521)	$ (109,514)	$ (480,007)	$ (2,927,994)	$ 44,069