Operating Segments and Related Information - Summary of information relating to operating segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Goodwill	$ 317,873		$ 317,873		$ 317,873
Total Assets	12,497,388		12,497,388		12,859,689
Net interest income	86,305	$ 70,755	232,289	$ 200,190
Noninterest income	30,933	33,259	97,724	97,715
Noninterest expense	70,736	73,487	210,204	190,611
Income before income taxes	44,138	32,396	116,045	117,659
Net income	35,661	25,941	93,924	93,523
Operating segment | Banking
Segment Reporting Information [Line Items]
Goodwill	294,773		294,773		294,773
Total Assets	12,352,413		12,352,413		12,746,833
Net interest income	90,916	74,672	244,820	211,377
Noninterest income	13,559	14,976	42,827	42,798
Noninterest expense	55,273	59,520	165,220	150,032
Income before income taxes	46,838	31,996	118,663	114,507
Net income	37,082	25,123	94,032	89,889
Operating segment | FirsTech
Segment Reporting Information [Line Items]
Goodwill	8,992		8,992		8,992
Total Assets	48,499		48,499		47,481
Net interest income	15	19	50	60
Noninterest income	5,578	5,030	16,333	14,700
Noninterest expense	5,109	4,519	14,601	13,086
Income before income taxes	484	530	1,782	1,674
Net income	353	384	1,300	1,214
Operating segment | Wealth Management
Segment Reporting Information [Line Items]
Goodwill	14,108		14,108		14,108
Total Assets	80,082		80,082		65,587
Noninterest income	12,514	13,746	42,425	39,333
Noninterest expense	7,682	7,679	23,533	20,961
Income before income taxes	4,832	6,068	18,892	18,373
Net income	3,756	4,719	14,688	14,285
Intersegment Eliminations
Segment Reporting Information [Line Items]
Goodwill	0		0		0
Total Assets	16,394		16,394		$ (212)
Net interest income	(4,626)	(3,936)	(12,581)	(11,247)
Noninterest income	(718)	(493)	(3,861)	884
Noninterest expense	2,672	1,769	6,850	6,532
Income before income taxes	(8,016)	(6,198)	(23,292)	(16,895)
Net income	$ (5,530)	$ (4,285)	$ (16,096)	$ (11,865)