Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ 52,926	$ 111,810	$ (1,799,021)	$ 185,843
Available for sale securities:
Unrealized gains arising during the period	4,570	40,760	112,331	74,029
Income tax expense related to unrealized gains	(1,175)	(10,484)	(28,892)	(19,041)
Reclassification adjustment for net realized (gains) losses in earnings	(323)	7,186	(190)	7,186
Income tax expense (benefit) related to realized losses	83	(1,848)	49	(1,848)
Net change in unrealized gains for available for sale securities	3,155	35,614	83,298	60,326
Junior subordinated debentures, at fair value:
Unrealized (losses) gains arising during the period	(37,450)	17,240	41,412	23,804
Income tax benefit (expense) related to unrealized gains	9,632	(4,459)	(10,651)	(6,103)
Net change in unrealized (losses) gains for junior subordinated debentures, at fair value	(27,818)	12,781	30,761	17,701
Other comprehensive (loss) income, net of tax	(24,663)	48,395	114,059	78,027
Comprehensive income (loss)	$ 28,263	$ 160,205	$ (1,684,962)	$ 263,870