FAIR VALUE (Fair value measurement recurring) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets
Securities available for sale	$ 3,020,568	$ 2,450,709
Equity securities with a readily determinable fair value	18,362
Level 1
Assets
Securities available for sale	7,497	25,414
Derivative assets	0	0
Liabilities
Derivative Liability	0	0
Level 2
Assets
Securities available for sale	3,013,071	2,425,295
Derivative assets	22,152	6,539
Liabilities
Derivative Liability	27,479	6,044
Level 3
Assets
Securities available for sale	0	0
Derivative assets	0	0
Liabilities
Derivative Liability	0	0
Forward commitments \| Level 1
Assets
Derivative assets	0
Forward commitments \| Level 2
Assets
Derivative assets	64
Forward commitments \| Level 3
Assets
Derivative assets	0
U.S. government corporations and agencies
Assets
Securities available for sale	8,950	31,951
Mortgage and asset-backed securities
Assets
Securities available for sale	2,480,677	2,026,698
Obligations of states and political subdivisions
Assets
Securities available for sale	512,579	374,974
Recurring Basis
Assets
Equity securities with a readily determinable fair value	18,362	17,086
Total assets at fair value	3,043,754	2,457,973
Liabilities
Total liabilities at fair value	27,688	6,443
Recurring Basis \| Level 1
Assets
Equity securities with a readily determinable fair value	0	0
Total assets at fair value	7,497	25,414
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Level 2
Assets
Equity securities with a readily determinable fair value	18,362	17,086
Total assets at fair value	3,035,287	2,431,834
Liabilities
Total liabilities at fair value	27,688	6,443
Recurring Basis \| Level 3
Assets
Equity securities with a readily determinable fair value	0	0
Total assets at fair value	970	725
Liabilities
Total liabilities at fair value	0	0
Recurring Basis \| Derivative financial instruments
Assets
Derivative assets	22,152	6,539
Liabilities
Derivative Liability	27,479	6,044
Recurring Basis \| Derivative financial instruments \| Level 1
Assets
Derivative assets	0	0
Liabilities
Derivative Liability	0	0
Recurring Basis \| Derivative financial instruments \| Level 2
Assets
Derivative assets	22,152	6,539
Liabilities
Derivative Liability	27,479	6,044
Recurring Basis \| Derivative financial instruments \| Level 3
Assets
Derivative assets	0	0
Liabilities
Derivative Liability	0	0
Recurring Basis \| Interest rate lock commitments
Assets
Derivative assets	970	725
Recurring Basis \| Interest rate lock commitments \| Level 1
Assets
Derivative assets	0	0
Recurring Basis \| Interest rate lock commitments \| Level 2
Assets
Derivative assets	0	0
Recurring Basis \| Interest rate lock commitments \| Level 3
Assets
Derivative assets	970	725
Recurring Basis \| Forward commitments
Assets
Derivative assets	64
Liabilities
Derivative Liability	209	399
Recurring Basis \| Forward commitments \| Level 1
Assets
Derivative assets	0
Liabilities
Derivative Liability	0	0
Recurring Basis \| Forward commitments \| Level 2
Assets
Derivative assets	64
Liabilities
Derivative Liability	209	399
Recurring Basis \| Forward commitments \| Level 3
Assets
Derivative assets	0
Liabilities
Derivative Liability	0	0
Recurring Basis \| U.S. government corporations and agencies
Assets
Securities available for sale	8,950	31,951
Recurring Basis \| U.S. government corporations and agencies \| Level 1
Assets
Securities available for sale	7,497	25,414
Recurring Basis \| U.S. government corporations and agencies \| Level 2
Assets
Securities available for sale	1,453	6,537
Recurring Basis \| U.S. government corporations and agencies \| Level 3
Assets
Securities available for sale	0	0
Recurring Basis \| Mortgage and asset-backed securities
Assets
Securities available for sale	2,480,677	2,026,698
Recurring Basis \| Mortgage and asset-backed securities \| Level 1
Assets
Securities available for sale	0	0
Recurring Basis \| Mortgage and asset-backed securities \| Level 2
Assets
Securities available for sale	2,480,677	2,026,698
Recurring Basis \| Mortgage and asset-backed securities \| Level 3
Assets
Securities available for sale	0	0
Recurring Basis \| Obligations of states and political subdivisions
Assets
Securities available for sale	512,579	374,974
Recurring Basis \| Obligations of states and political subdivisions \| Level 1
Assets
Securities available for sale	0	0
Recurring Basis \| Obligations of states and political subdivisions \| Level 2
Assets
Securities available for sale	512,579	374,974
Recurring Basis \| Obligations of states and political subdivisions \| Level 3
Assets
Securities available for sale	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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