LOANS AND ALLOWANCE FOR CREDIT LOSSES - COVID-19 RELATED LOAN MODIFICATIONS (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Troubled Debt Restructurings disclosures
Total loans	$ 5,065,092	$ 4,433,151
Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	$ 3,935,823	3,595,931
Percentage of loans	100.00%
Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	$ 793,182
Percentage of loans	20.00%
PPP Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	$ 511,065
Percentage of loans	13.00%
Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	$ 2,631,576
Percentage of loans	67.00%
Residential Real Estate - Owner Occupied
Troubled Debt Restructurings disclosures
Total loans	$ 885,325
Residential Real Estate - Owner Occupied | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	885,325	949,568
Residential Real Estate - Owner Occupied | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	51,570
Residential Real Estate - Owner Occupied | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	833,755
Residential Real Estate - Non Owner Occupied
Troubled Debt Restructurings disclosures
Total loans	254,700
Residential Real Estate - Non Owner Occupied | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	254,700	258,803
Residential Real Estate - Non Owner Occupied | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	58,754
Residential Real Estate - Non Owner Occupied | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	195,946
Commercial Real Estate
Troubled Debt Restructurings disclosures
Total loans	1,322,290
Commercial Real Estate | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	1,322,290	1,303,000
Commercial Real Estate | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	491,314
Commercial Real Estate | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	830,976
Commercial & industrial
Troubled Debt Restructurings disclosures
Total loans	904,727
Commercial & industrial | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	904,727	477,236
Commercial & industrial | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	141,720
Commercial & industrial | PPP Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	511,065
Commercial & industrial | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	251,942
Construction & land development
Troubled Debt Restructurings disclosures
Total loans	157,254
Construction & land development | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	157,254	159,702
Construction & land development | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	28,927
Construction & land development | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	128,327
Lease Financing Receivables
Troubled Debt Restructurings disclosures
Total loans	11,864
Lease Financing Receivables | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	11,864	14,040
Lease Financing Receivables | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	2,443
Lease Financing Receivables | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	9,421
Warehouse lines of credit
Troubled Debt Restructurings disclosures
Total loans	1,029,779
Home equity lines of credit
Troubled Debt Restructurings disclosures
Total loans	265,266
Home equity lines of credit | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	265,266	293,186
Home equity lines of credit | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	13,776
Home equity lines of credit | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	251,490
Consumer: Credit cards | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	14,265	17,836
Consumer: Overdrafts | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	488	1,522
Consumer
Troubled Debt Restructurings disclosures
Total loans	134,397
Consumer | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	134,397
Consumer | Covid-19 Accommodations | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	4,678
Consumer | Other Loans | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	129,719
Consumer: Automobile loan | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	41,059	52,923
Other consumer | Traditional Banking
Troubled Debt Restructurings disclosures
Total loans	$ 78,585	$ 68,115