CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
OPERATING ACTIVITIES:
Net income	$ 136,515	$ 60,776	$ 85,385
Adjustments to reconcile net income to net cash provided from (used by) operating activities:
Depreciation	15,232	14,701	13,464
Deferred income and expense, net of amortization	(6,571)	1,972	(1,323)
Amortization of core deposit intangibles	6,047	6,246	7,061
Loss (gain) on sale of securities, net	837	2,080	(843)
Net change in valuation of financial instruments carried at fair value	(3,775)	2,844	2,620
Purchases of securities—trading	0	0	(1,725)
Proceeds from sales of securities—trading	0	1,258	7,839
Principal repayments and maturities of securities—trading	100	1,849	3,746
Gain (Loss) on Sale of Branches, including loans and deposits	0	12,189	0
(Increase) decrease in deferred taxes	(3,498)	56,267	7,883
Increase (decrease) in current taxes payable	3,938	(2,965)	(2,184)
Equity-based compensation	6,554	5,965	4,305
Increase in cash surrender value of BOLI	(4,471)	(4,057)	(4,507)
Gain on sale of loans, net of capitalized servicing rights	(15,066)	(15,225)	(17,713)
Gain on disposal of real estate held for sale and property and equipment	(833)	(4,295)	(1,389)
PROVISION FOR LOAN LOSSES	8,500	8,000	6,030
Provision for real estate held for sale	387	256	876
Origination of loans held for sale	(896,461)	(807,137)	(1,063,328)
Proceeds from sales of loans held for sale	781,879	1,027,989	880,890
Net change in:
Other assets	(15,861)	2,546	3,759
Other liabilities	17,322	(179)	(6,664)
Net cash provided from (used by) operating activities	30,775	346,702	(75,818)
INVESTING ACTIVITIES:
Purchases of securities—available-for-sale	(913,951)	(838,247)	(243,115)
Principal repayments and maturities of securities—available-for-sale	173,454	187,080	191,534
Proceeds from sales of securities—available-for-sale	214,609	522,564	369,755
Purchases of securities—held-to-maturity	(9,612)	(6,490)	(60,344)
Principal repayments and maturities of securities—held-to-maturity	33,152	11,817	11,009
Loan originations, net of repayments	(416,218)	(288,951)	(75,922)
Purchases of loans and participating interest in loans	(33,680)	(126,508)	(235,527)
Proceeds from sales of other loans	9,853	21,923	184,525
Proceeds from Divestiture of Businesses	(1,574)
Net cash (paid) received from acquisitions and branch divestitures		113,222	0
Purchases of property and equipment	(23,094)	(12,244)	(16,239)
Proceeds from Sale of Property, Plant, and Equipment	7,768	20,121	14,513
Proceeds from FHLB stock repurchase program	143,175	118,304	80,681
Purchase of FHLB stock	(163,683)	(116,132)	(77,130)
Other	3,583	254	2,707
Net cash (used by) provided from investing activities	(976,218)	(393,287)	146,447
FINANCING ACTIVITIES:
Increase in deposits, net	503,814	222,334	66,346
Repayment of long term FHLB borrowing	(10)	(9)	(95,009)
Advances, net of (repayments) of overnight and short-term FHLB borrowings	540,000	(54,000)	16,400
Increase (decrease) in other borrowings, net	7,870	(9,825)	7,360
Cash dividends paid	(59,280)	(65,759)	(28,282)
Cash paid for repurchase of common stock	(34,401)	(31,045)	(50,772)
Payments Related to Tax Withholding for Share-based Compensation	1,554	1,630	870
Net cash provided from (used by) financing activities	956,439	60,066	(84,827)
NET CHANGE IN CASH AND CASH EQUIVALENTS	10,996	13,481	(14,198)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	261,200	247,719	261,917
CASH AND CASH EQUIVALENTS, END OF YEAR	272,196	261,200	247,719
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid in cash	28,098	18,875	16,722
Taxes paid in cash	21,664	35,500	36,153
NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Loans, net of discounts, specific loss allowances and unearned income, transferred to real estate owned and other repossessed assets	1,645	10	9,146
Dividends accrued but not paid until after period end	13,778	8,226	7,662
ACQUISITIONS (DISPOSITIONS):
Assets Disposed	915,821
Assets acquired (disposed)		(259,398)	0
Liabilities Transfered	$ 832,278
Liabilities assumed (transferred)		$ (160,465)	$ 0