Business Combinations - Pro-forma Information (Details) - ANH - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Pro-forma information
Interest income	$ 85,120	$ 105,314
Interest expense	(54,289)	(70,317)
Recovery of (provision for) loan losses	8	(39,860)
Non-interest income	91,690	19,463
Non-interest expense	(79,584)	(296,474)
Income (loss) before provision for income taxes	42,945	(281,874)
Income tax benefit (expense)	(8,681)	7,937
Net income (loss)	34,264	$ (273,937)
Nonrecurring transaction costs excluded from pro forma non-interest expense	$ 6,300