Segment Information - Results of Operations and Selected Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net interest income	$ 75,507	$ 77,206
Noninterest income	43,650	39,935
Income before taxes	43,709	52,178
Total assets	12,624,431		$ 9,405,612
Operating Segments [Member] | Metropolitan Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	19,608	19,333
Noninterest income	9,773	5,144
Income before taxes	18,171	13,924
Total assets	3,514,435		2,627,874
Operating Segments [Member] | Community Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	44,568	42,770
Noninterest income	16,845	14,976
Income before taxes	31,339	29,769
Total assets	6,868,166		5,821,220
Operating Segments [Member] | Pegasus [Member]
Segment Reporting Information [Line Items]
Net interest income	7,620	5,359
Noninterest income	191	384
Income before taxes	2,827	1,645
Total assets	1,461,916		1,045,699
Operating Segments [Member] | Worthington [Member]
Segment Reporting Information [Line Items]
Net interest income	1,694
Noninterest income	133
Income before taxes	385
Total assets	517,238
Operating Segments [Member] | Other Financial Services [Member]
Segment Reporting Information [Line Items]
Net interest income	2,913	9,882
Noninterest income	12,983	11,575
Income before taxes	6,045	5,951
Total assets	91,699		71,694
Operating Segments [Member] | Executive, Operations & Support [Member]
Segment Reporting Information [Line Items]
Net interest income	(907)	(407)
Noninterest income	42,574	49,731
Income before taxes	23,648	42,340
Total assets	1,591,150		1,201,974
Eliminations [Member]
Segment Reporting Information [Line Items]
Net interest income	11	269
Noninterest income	(38,849)	(41,875)
Income before taxes	(38,706)	$ (41,451)
Total assets	$ (1,420,173)		$ (1,362,849)