Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock	Noncontrolling Interest
Balance at beginning of the period at Dec. 31, 2018	$ 5,271,515	$ 30,832	$ 20,694	$ (99,738)	$ 5,413,952	$ (108,492)	$ 14,267
Stockholders' Equity [Roll Forward]
Reissuance of treasury shares	260		237			23
Amortization of restricted stock	20		20
Cumulative effect of accounting change	0			(785)	785
Other comprehensive income (loss)	86,774			86,774
Net loss attributable to American National	258,217				258,217
Cash dividends to common stockholders	(22,101)				(22,101)
Contributions	3						3
Distributions	(419)						(419)
Net loss attributable to noncontrolling interest	(1,350)						(1,350)
Balance at end of the period at Mar. 31, 2019	5,592,919	30,832	20,951	(13,749)	5,650,853	(108,469)	12,501
Balance at beginning of the period at Dec. 31, 2019	5,995,763	30,832	21,011	99,518	5,946,857	(108,469)	6,014
Stockholders' Equity [Roll Forward]
Amortization of restricted stock	20		20
Cumulative effect of accounting change	(34,702)			0	(34,702)
Other comprehensive income (loss)	(111,571)			(111,571)
Net loss attributable to American National	(220,444)				(220,444)
Cash dividends to common stockholders	(22,047)				(22,047)
Contributions	546						546
Distributions	(323)						(323)
Net loss attributable to noncontrolling interest	(153)						(153)
Balance at end of the period at Mar. 31, 2020	$ 5,607,089	$ 30,832	$ 21,031	$ (12,053)	$ 5,669,664	$ (108,469)	$ 6,084