COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 9,307,819	$ 9,201,665
Unused Commitments to Extend Credit	2,706,755
Commercial
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	2,477,773	2,465,877
Unused Commitments to Extend Credit	1,090,309
Lease financing
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	82,602	88,364
Unused Commitments to Extend Credit	0
Construction real estate
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	500,311	493,182
Unused Commitments to Extend Credit	462,460
Commercial real estate - investor
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,278,257	4,194,651
Unused Commitments to Extend Credit	152,602
Commercial real estate - investor
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	3,180,037
Commercial real estate-owner
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,098,220
Unused Commitments to Extend Credit	45,889
Residential real estate
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,061,792	1,055,949
Unused Commitments to Extend Credit	30,807
Home equity
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	781,243	771,869
Unused Commitments to Extend Credit	717,625
Installment
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	80,085	82,589
Unused Commitments to Extend Credit	21,457
Credit card
Other Commitments [Line Items]
Loans and Leases Receivable, Net of Deferred Income	45,756	$ 49,184
Unused Commitments to Extend Credit	$ 185,606