Business Combinations - Pro-forma Information (Details) - USD ($) $ in Thousands		12 Months Ended
	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pro-forma information
Bargain purchase gain			$ 30,728
Owens Realty Mortgage, Inc.
Pro-forma information
Interest income		$ 232,706		$ 181,780
Interest expense		(152,428)		(111,371)
Provision for loan losses		(3,684)		(1,462)
Noninterest income		145,393		157,049
Noninterest expense		(180,140)		(155,704)
Income before provision for income taxes		41,847		70,292
Income tax benefit (provision)		10,545		(1,945)
Net income		$ 52,392		68,347
Nonrecurring transaction costs excluded from pro forma non-interest expense			9,200
Bargain purchase gain	$ 30,728
Knight Capital
Pro-forma information
Interest income			229,916	169,499
Interest expense			(151,880)	(109,238)
Provision for loan losses			(3,684)	(1,701)
Noninterest income			223,197	192,181
Noninterest expense			(229,648)	(201,454)
Income before provision for income taxes			67,901	49,287
Income tax benefit (provision)			10,552	(1,386)
Net income			78,453	$ 47,901
Nonrecurring transaction costs excluded from pro forma non-interest expense			$ 2,200