Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Operating Activities
Net income	$ 38,904	$ 9,387	$ 78,809	$ 36,047
Adjustments reconciling net income to net cash provided by (used in) operating activities:
Depreciation			5,292	4,546
Net losses on sale or disposal of premises and equipment including write-downs			70	91
Net write-downs on other assets			3,580	0
Provision for loan losses	4,668	9,110	8,076	10,911	$ 16,667
Net losses on sale of other real estate owned including write-downs			84	385
Share-based compensation expense			1,514	4,151
Amortization of intangible assets	3,121	2,252	6,253	3,186
Amortization of operating lease right-of-use assets			3,029
Provision for deferred taxes			3,962	(1,448)
Net amortization of investment securities available for sale			1,653	2,896
Net (gain) loss on securities	(69)	123	(135)	86
Accretion of discount on purchased loans			(6,125)	(4,340)
Amortization of premium on purchased loan pools			673	1,016
Accretion on other borrowings			41	65
Accretion on subordinated deferrable interest debentures			684	661
Originations of mortgage loans held for sale			(798,429)	(882,484)
Payments received on mortgage loans held for sale			488	773
Proceeds from sales of mortgage loans held for sale			745,876	778,216
Net gains on sale of mortgage loans held for sale			(27,222)	(16,860)
Originations of SBA loans			(33,191)	(16,246)
Proceeds from sales of SBA loans			29,952	21,038
Net gains on sale of SBA loans			(2,476)	(1,840)
Increase in cash surrender value of bank owned life insurance			(968)	(782)
Changes in FDIC loss-share payable, net of cash payments			3,431	1,611
Change attributable to other operating activities			3,955	2,856
Net cash provided by (used in) operating activities			28,876	(55,465)
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks			10,064	0
Purchases of securities available for sale			(219,352)	(155,476)
Proceeds from prepayments and maturities of securities available for sale			99,408	69,948
Proceeds from sales of securities available for sale			64,995	46,437
Net (increase) decrease in other investments			(17,949)	9,171
Net increase in loans, excluding purchased loans			(880,247)	(361,575)
Payments received on purchased loans			245,411	108,727
Payments received on purchased loan pools			20,955	37,742
Purchases of premises and equipment			(4,610)	(3,066)
Proceeds from sales of premises and equipment			762	507
Proceeds from sales of other real estate owned			4,854	5,875
Payments paid to FDIC under loss-share agreements			(2,322)	(1,017)
Net cash and cash equivalents received in acquisitions			0	52,016
Net cash used in investing activities			(678,031)	(190,711)
Financing Activities, net of effects of business combinations
Net decrease in deposits			(66,943)	(28,861)
Net decrease in securities sold under agreements to repurchase			(17,077)	(19,636)
Proceeds from other borrowings			415,000	1,150,000
Repayment of other borrowings			(2,179)	(753,579)
Proceeds from exercise of stock options			54	846
Dividends paid - common stock			(9,511)	(7,558)
Purchase of treasury shares			(11,561)	(985)
Net cash provided by financing activities			307,783	340,227
Net (decrease) increase in cash and cash equivalents			(341,372)	94,051
Cash and cash equivalents at beginning of period			679,527	330,658	330,658
Cash and cash equivalents at end of period	$ 338,155	$ 424,709	338,155	424,709	$ 679,527
Cash paid during the period for:
Interest			51,250	23,213
Income taxes			21,377	4,018
Loans (excluding purchased loans) transferred to other real estate owned			443	1,691
Purchased loans transferred to other real estate owned			2,432	536
Loans transferred from loans held for sale to loans held for investment			0	180,750
Loans transferred from loans held for investment to loans held for sale			64,773	2,796
Loans provided for the sales of other real estate owned			144	53
Initial recognition of operating lease right-of-use assets			27,286
Initial recognition of operating lease liabilities			29,651
Right-of-use assets obtained in exchange for new operating lease liabilities			262
Assets acquired in business acquisitions			373	3,058,197
Liabilities assumed in business acquisitions			(1,922)	2,408,837
Issuance of common stock in acquisitions			0	547,127
Change in unrealized gain (loss) on securities available for sale, net of tax			21,700	(11,585)
Change in unrealized gain (loss) on cash flow hedge, net of tax			$ (412)	$ 294