Segment and Related Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) item segment	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Information about the revenues, operating results, goodwill and assets
Number of primary business units | item			2
Number of reportable segments | segment			3
Net interest income (expense)	$ 112,056	$ 107,916	$ 212,047	$ 213,598
Provision for (reversal of) credit losses	5,336	(28,720)	5,451	(33,829)
Noninterest income	239,273	339,899	455,701	757,484
Noninterest expense	298,543	343,368	584,893	710,030
Income before income taxes	47,450	133,167	77,404	294,881
Goodwill	267,447		267,447		$ 267,447
Total assets	16,715,739		16,715,739		18,689,080
Operating Segments | Banking
Information about the revenues, operating results, goodwill and assets
Net interest income (expense)	101,259	105,468	193,329	209,352
Provision for (reversal of) credit losses	5,025	(28,775)	4,975	(33,950)
Noninterest income	12,467	10,242	25,237	21,566
Noninterest expense	57,331	57,514	115,761	113,302
Income before income taxes	51,370	86,971	97,830	151,566
Goodwill	247,368		247,368		247,368
Total assets	13,826,898		13,826,898		14,944,249
Operating Segments | Broker-Dealer
Information about the revenues, operating results, goodwill and assets
Net interest income (expense)	12,578	10,682	24,096	21,196
Provision for (reversal of) credit losses	311	55	476	121
Noninterest income	87,651	83,463	148,341	182,086
Noninterest expense	90,817	87,234	171,464	178,638
Income before income taxes	9,101	6,856	497	24,523
Goodwill	7,008		7,008		7,008
Total assets	2,659,850		2,659,850		3,673,346
Operating Segments | Mortgage Origination Segment
Information about the revenues, operating results, goodwill and assets
Net interest income (expense)	(1,291)	(5,953)	(3,127)	(13,051)
Noninterest income	140,082	241,965	283,276	552,409
Noninterest expense	133,169	186,963	268,027	397,297
Income before income taxes	5,622	49,049	12,122	142,061
Goodwill	13,071		13,071		13,071
Total assets	1,820,074		1,820,074		2,207,822
Operating Segments | Corporate
Information about the revenues, operating results, goodwill and assets
Net interest income (expense)	(3,190)	(4,687)	(6,580)	(9,379)
Noninterest income	2,080	6,877	3,846	7,383
Noninterest expense	17,561	12,072	30,354	21,660
Income before income taxes	(18,671)	(9,882)	(33,088)	(23,656)
Total assets	2,444,889		2,444,889		2,940,670
All Other and Eliminations
Information about the revenues, operating results, goodwill and assets
Net interest income (expense)	2,700	2,406	4,329	5,480
Noninterest income	(3,007)	(2,648)	(4,999)	(5,960)
Noninterest expense	(335)	(415)	(713)	(867)
Income before income taxes	28	$ 173	43	$ 387
Total assets	$ (4,035,972)		$ (4,035,972)		$ (5,077,007)