DERIVATIVES - Derivatives Recorded at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative assets	$ 125,632	$ 290,144
Derivative liabilities	36,996	119,762
Interest rate swaps
Derivative [Line Items]
Derivative asset, variation margin accounts	188,000	237,700
Interest rate swaps | Other assets
Derivative [Line Items]
Derivative assets	0	0
Interest rate swaps | Accrued expenses and other liabilities
Derivative [Line Items]
Derivative liabilities	3,919	25
Interest rate lock commitments | Other assets
Derivative [Line Items]
Derivative assets	112,314	289,355
Interest rate lock commitments | Accrued expenses and other liabilities
Derivative [Line Items]
Derivative liabilities	2,924	281
Forward Loan Sale Commitments | Other assets
Derivative [Line Items]
Derivative assets	0	0
TBAs | Other assets
Derivative [Line Items]
Derivative assets	13,318	789
TBAs | Accrued expenses and other liabilities
Derivative [Line Items]
Derivative liabilities	$ 30,153	$ 119,456