Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 121,027	$ 73,548	$ 72,100
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	10,014	9,196	9,519
Net losses (gains) on sale or disposal of premises and equipment	133	1,264	992
Provision for loan losses	16,667	8,364	4,091
Net write-downs and losses on sale of other real estate owned	1,301	500	1,953
Share-based compensation expense	6,241	3,316	2,261
Amortization of intangible assets	9,512	3,932	4,376
Provision for deferred taxes	1,374	12,430	847
Net amortization of investment securities available for sale	4,891	6,384	7,057
Net loss (gain) on securities	37	(37)	(94)
Accretion of discount on purchased loans	(11,918)	(11,308)	(16,637)
Amortization of premium on purchased loan pools	1,825	3,543	5,653
Net amortization (accretion) on other borrowings	96	95	(76)
Amortization of subordinated deferrable interest debentures	1,345	1,322	1,453
Originations of mortgage loans held for sale	(1,768,934)	(1,502,314)	(1,403,954)
Payments received on mortgage loans held for sale	986	1,238	1,390
Proceeds from sales of mortgage loans held for sale	1,542,755	1,370,008	1,340,668
Net gains on mortgage loans held for sale	(37,336)	(46,913)	(52,198)
Originations of SBA loans	(27,820)	(33,104)	(69,512)
Proceeds from sales of SBA loans	33,675	30,696	28,268
Net gains on sales of SBA loans	(2,728)	(4,590)	(3,974)
Increase in cash surrender value of bank owned life insurance	(1,819)	(1,588)	(1,734)
Changes in FDIC loss-share receivable/payable, net of cash payments received	5,156	3,005	11,798
Increase in interest receivable	(10,965)	(3,728)	(1,004)
Increase decrease in interest payable	2,411	1,757	446
Increase (decrease) in taxes payable	4,032	(473)	(8,328)
Change attributable to other operating activities	(10,761)	10,895	(5,128)
Net cash used in operating activities	(108,803)	(62,562)	(69,767)
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks	746	0	0
Purchases of securities available for sale	(290,649)	(113,261)	(200,823)
Proceeds from prepayments and maturities of securities available for sale	152,393	115,166	131,390
Proceeds from sale of securities available for sale	68,727	3,090	75,990
Net decrease (increase) in other investments	33,515	11,046	(17,936)
Net increase in loans, excluding purchased loans	(470,156)	(1,016,409)	(1,063,345)
Payments received on purchased loans	330,226	210,470	247,452
Purchases of purchased loan pools	0	0	(152,091)
Payments received on purchased loan pools	71,817	112,330	171,087
Purchases of premises and equipment	(10,009)	(3,760)	(10,977)
Proceeds from sale of premises and equipment	588	16	295
Proceeds from sales of other real estate owned	11,784	14,920	22,483
Payments received from (paid to) FDIC under loss-sharing agreements	(3,791)	(515)
Payments received from (paid to) FDIC under loss-sharing agreements			816
Net cash proceeds received from (paid in) acquisitions	51,495	0	(7,206)
Net cash used in investing activities	(53,314)	(666,907)	(802,865)
Financing Activities, net of effects of business combinations
Net increase in deposits	853,051	1,050,682	294,513
Net decrease in securities sold under agreements to repurchase	(10,254)	(22,867)	(10,080)
Proceeds from other borrowings	1,530,000	1,837,692	635,886
Repayment of other borrowings	(1,844,258)	(2,079,554)	(231,020)
Issuance of common stock	0	88,656	0
Proceeds from exercise of stock options	914	2,669	964
Dividends paid - common stock	(16,405)	(14,650)	(8,584)
Purchase of treasury shares	(2,062)	(886)	(1,225)
Net cash provided by financing activities	510,986	861,742	680,454
Net increase (decrease) in cash and cash equivalents	348,869	132,273	(192,178)
Cash and cash equivalents at beginning of period	330,658	198,385	390,563
Cash and cash equivalents at end of period	679,527	330,658	198,385
Cash paid during the year for:
Interest	67,523	32,465	19,248
Income taxes	20,026	38,939	40,575
Loans (excluding purchased loans) transferred to other real estate owned	4,124	4,372	3,203
Purchased loans transferred to other real estate owned	6,393	5,023	7,229
Loans transferred from loans held for sale to loans held for investment	10,817	212,850	119,352
Loans transferred from loans held for investment to loans held for sale	8,831	119,389	0
Loans provided for the sales of other real estate owned	931	1,334	1,942
Assets acquired in business combinations	3,064,615	0	561,440
Liabilities assumed in business combinations	2,415,212	0	465,048
Issuance of common stock in acquisitions	547,127	0	72,455
Issuance of common stock in exchange for equity investment in US Premium Finance Holding Company	0	5,844	0
Change in unrealized gain (loss) on securities available for sale, net of tax	(3,266)	(338)	(4,435)
Change in unrealized gain on cash flow hedge, net of tax	$ 112	$ 116	$ 24