COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 10,200,809	$ 9,201,665
Unused Commitments to Extend Credit	2,889,365
Commercial
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,292,313	2,465,877
Unused Commitments to Extend Credit	1,287,307
Lease financing
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	74,742	88,364
Unused Commitments to Extend Credit	0
Construction real estate
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	575,648	493,182
Unused Commitments to Extend Credit	404,441
Commercial real estate - investor
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,347,125	4,194,651
Unused Commitments to Extend Credit	142,502
Commercial real estate - investor
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,263,213
Commercial real estate-owner
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,083,912
Unused Commitments to Extend Credit	47,943
Residential real estate
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,027,702	1,055,949
Unused Commitments to Extend Credit	31,513
Home equity
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	754,743	771,869
Unused Commitments to Extend Credit	750,994
Installment
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	84,629	82,589
Unused Commitments to Extend Credit	20,138
Credit card
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	43,907	$ 49,184
Unused Commitments to Extend Credit	$ 204,527