CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 25,783	$ 20,110
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Amortization and accretion of premiums and discounts on securities, net	1,253	542
Accretion of loan discounts, net	(2,917)	(2,470)
Amortization of deposit premiums	(415)	(567)
Amortization of core deposit intangibles	622	760
Amortization and accretion of borrowing and debt valuation allowance, net	210	210
Amortization of issuance costs of subordinated notes	72	72
Provision for loan losses	11,560	7,655
Depreciation	955	1,048
Net gain on sale of available-for-sale securities	(66)	(294)
Net loss on sale of real estate acquired by foreclosure	0	147
Net gain on loans held-for-sale	0	(84)
Net gain on sale of guaranteed portion of loans	(2,053)	(2,805)
Net market value loss on equity investments	262	0
Originations of loans held-for-sale	(22,595)	0
Proceeds from sales of and principal collected on loans held-for-sale	26,812	13,903
Writedown of real estate acquired by foreclosure	0	185
Stock-based compensation expense	2,471	1,059
Deferred tax benefit	(3,770)	(1,201)
Net change in accrued interest receivable and other assets, net	(6,165)	15,222
Net change in accrued interest payable and other liabilities, net	(1,205)	(3,473)
Net cash provided by operating activities	30,814	50,019
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from the maturities or calls and paydowns of available-for-sale securities	36,322	37,329
Proceeds from the sale of available-for-sale securities	24,424	279,168
Purchases of available-for-sale securities	(65,686)	(729,200)
Proceeds from the maturities or calls and paydowns of held-to-maturity securities	2,433	3,815
Purchases of held-to-maturity securities	(3,627)	0
Proceeds from sales of guaranteed portion of loans	0	33,606
Proceeds from sales of real estate acquired by foreclosure	0	3,967
Purchases of Federal Home Loan Bank of Dallas stock, net of redemptions	(4,796)	(7,329)
Purchases of Federal Reserve Bank stock	(107)	(24)
Net increase in loans held for investment	(42,363)	(68,624)
Investment in construction of premises and purchases of other fixed assets	(168)	(212)
Net cash used in investing activities	(53,568)	(447,504)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposit accounts	29,322	(13,711)
Net (decrease) increase in securities sold under agreements to repurchase	(1,032)	1,728
Net proceeds from other short-term borrowed funds	87,000	155,000
Proceeds from issuance of common stock due to exercise of stock options	1,761	456
Payments of cash dividends	(3,727)	0
Net cash provided by financing activities	113,324	143,473
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	90,570	(254,012)
CASH AND CASH EQUIVALENTS:
Beginning of period	140,681	389,007
End of period	231,251	134,995
NONCASH ACTIVITIES:
Noncash investing and financing activities - acquisition of real estate through foreclosure of collateral	5,963	5,270
Transfer of loans to held-for-sale	0	7,860
SUPPLEMENTAL INFORMATION:
Interest paid	18,548	15,108
Income taxes paid	$ 8,000	$ 7,300