FAIR VALUE (Fair Value Measurement Recurring) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 6,108,346	$ 3,294,361
Equity securities with a readily determinable fair value	19,629	18,435
U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	166,779	184,676
Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,635,227	707,190
Commercial mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	174,153	68,865
Commercial mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	252,767	436,325
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,069,266	691,579
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,742	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,026	0
Derivative financial instruments	0	0
Derivative liabilities	0	0
Level 1 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Level 1 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	6,125,949	3,304,293
Derivative financial instruments	44,102	17,527
Derivative liabilities	51,962	21,462
Level 2 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Level 2 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	15
Derivative liabilities	697	113
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Derivative financial instruments	0	0
Derivative liabilities	0	0
Level 3 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	1,827	637
Level 3 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	6,173,904	3,331,019
Total liabilities at fair value	52,659	21,575
Recurring Basis | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,026	8,503
Recurring Basis | U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	166,779	184,676
Recurring Basis | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,635,227	707,190
Recurring Basis | Mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,355,270	766,726
Recurring Basis | Mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,449,116	430,497
Recurring Basis | Commercial mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	174,153	68,865
Recurring Basis | Commercial mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	252,767	436,325
Recurring Basis | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,069,266	691,579
Recurring Basis | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,742	0
Recurring Basis | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value	19,629	18,435
Recurring Basis | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	44,102	17,527
Recurring Basis | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	1,827	681
Recurring Basis | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	51,962	21,462
Recurring Basis | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	15
Derivative liabilities	697	113
Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2,026	8,503
Total liabilities at fair value	0	0
Recurring Basis | Level 1 | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,026	8,503
Recurring Basis | Level 1 | U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Commercial mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Commercial mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value	0	0
Recurring Basis | Level 1 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 1 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 1 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Recurring Basis | Level 1 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	0	0
Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	6,170,051	3,321,835
Total liabilities at fair value	52,659	21,575
Recurring Basis | Level 2 | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 2 | U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	166,779	184,676
Recurring Basis | Level 2 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,635,227	707,190
Recurring Basis | Level 2 | Mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,355,270	766,726
Recurring Basis | Level 2 | Mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,449,116	430,497
Recurring Basis | Level 2 | Commercial mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	174,153	68,865
Recurring Basis | Level 2 | Commercial mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	252,767	436,325
Recurring Basis | Level 2 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,069,266	691,579
Recurring Basis | Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,742	0
Recurring Basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value	19,629	18,435
Recurring Basis | Level 2 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	44,102	17,527
Recurring Basis | Level 2 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 2 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	51,962	21,462
Recurring Basis | Level 2 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	15
Derivative liabilities	697	113
Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1,827	681
Total liabilities at fair value	0	0
Recurring Basis | Level 3 | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | U.S. agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Commercial mortgage-backed securities - agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Commercial mortgage-backed securities - non-agency
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Recurring Basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities with a readily determinable fair value	0	0
Recurring Basis | Level 3 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Recurring Basis | Level 3 | Interest rate lock commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	1,827	681
Recurring Basis | Level 3 | Derivative financial instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Recurring Basis | Level 3 | Forward commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Derivative liabilities	$ 0	$ 0