NOTE 9 - BUSINESS SEGMENT INFORMATION - Intercompany Eliminations (Details) - Intercompany Eliminations - Commercial Banking - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Segment Reporting [Line Items]
Equity in net income of subsidiary bank	$ 44,154	$ 43,947	$ 127,748	$ 108,202
Investment in subsidiary bank	1,380,120	1,331,566	1,380,120	1,331,566
QCBT
Segment Reporting [Line Items]
Equity in net income of subsidiary bank	9,554	8,371	31,014	25,155
Investment in subsidiary bank	303,959	298,385	303,959	298,385
CRBT
Segment Reporting [Line Items]
Equity in net income of subsidiary bank	21,670	21,959	60,757	50,996
Investment in subsidiary bank	483,615	453,386	483,615	453,386
CSB
Segment Reporting [Line Items]
Equity in net income of subsidiary bank	5,663	5,760	17,273	15,059
Investment in subsidiary bank	203,081	190,208	203,081	190,208
GB
Segment Reporting [Line Items]
Equity in net income of subsidiary bank	7,267	7,857	18,704	16,992
Investment in subsidiary bank	$ 389,465	$ 389,587	$ 389,465	$ 389,587