Condensed Consolidated Statements of Shareholder's Equity (Unaudited) - USD ($) $ in Thousands		Total	Preferred Stock	Common Stock	Surplus	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Non-Controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment related to ASU adoptions | ASU 2016-02, 2017-12, 2018-02	[1]	$ 3,460				$ 38,896	$ (35,436)
Balance, as adjusted		13,515,989	$ 229,475	$ 2,230	$ 14,545,849	(1,068,302)	(222,284)	$ 29,021
Balance, beginning of period at Dec. 31, 2018		13,512,529	229,475	2,230	14,545,849	(1,107,198)	(186,848)	29,021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		140,981				140,425		556
Other comprehensive income (loss), net of tax		74,149					74,149
Issuance of common stock		802			802
Preferred stock dividends		(4,485)			(4,485)
Capital contribution		101						101
Balance, end of period at Mar. 31, 2019		13,727,537	229,475	2,230	14,542,166	(927,877)	(148,135)	29,678
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment related to ASU adoptions | ASU 2016-13		(150,213)				(150,213)
Balance, as adjusted		13,236,376	229,475	2,230	14,043,727	(1,067,440)	(1,072)	29,456
Balance, beginning of period at Dec. 31, 2019		13,386,589	229,475	2,230	14,043,727	(917,227)	(1,072)	29,456
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income		(2,237,285)				(2,237,786)		501
Other comprehensive income (loss), net of tax		363,411					363,411
Preferred stock dividends		(4,155)			(4,155)
Capital contribution		7						7
Balance, end of period at Mar. 31, 2020		$ 11,358,354	$ 229,475	$ 2,230	$ 14,039,572	$ (3,305,226)	$ 362,339	$ 29,964

[1] Related to the Company's adoption of ASU 2016-02, ASU 2017-12 and ASU 2018-02 on January 1, 2019.