SUPPLEMENTAL CASH FLOW INFORMATION - Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash paid for:
Interest on borrowings	$ 94,872	$ 107,010	$ 98,194
Income tax	16,713	13,495	7,175
Operating cash flow from operating leases	13,464	10,219	0
Non-cash investing and financing activities:
Additions to OREO	7,249	40,398	48,767
Additions to auto and other repossed properties	36,203	47,643	52,023
Capitalization of servicing assets	4,864	4,039	3,864
Loan securitizations	221,491	235,258	233,175
Loans held for investment transferred to held for sale	10,817	24,470	90,319
Loans held for sale transferred to held for investment	0	0	2,179
Payable On Unsettled Securities Purchases	24,033	0	0
ROU asset obtained in exchange for operating lease liabilities	1,328	10,762	0
Adoption of lease accounting standard:
ROU assets operating leases	103,186	61,327
Operating Lease Liability	106,502	64,259
Acquisition (see Note 2):
Consideration	1,280,424	0	0
Fair value of assets acquired	5,561,564	0	0
Liabilities assumed	4,291,674	0	0
Accounting Standards Update 2016-02 [Member]
Adoption of lease accounting standard:
ROU assets operating leases	0	57,178	0
Operating Lease Liability	$ 0	$ 59,818	$ 0