Consolidated Statements of Cash Flows (Unaudited) - USD ($)			3 Months Ended		12 Months Ended
	Jan. 01, 2019		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income			$ 26,751,000	$ 35,225,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation and amortization			6,992,000	4,101,000
Change In Unamortized Net Loan Costs And Premiums			(735,000)	(453,000)
Provision for credit losses			25,000,000	1,000,000
Deferred income tax expense			3,108,000	539,000
Net unrealized (gain) loss on equity securities			1,801,000	(907,000)
Net loss on bank premises and equipment			420,000	25,000
Realized gain on sale leaseback transaction			(145,000)	(145,000)
Stock based compensation			850,000	915,000
Increase in cash surrender value of life insurance policies			(1,276,000)	(972,000)
Gain Realized on Life Insurance Policies			(357,000)	0
Operating Lease, Payments			(2,926,000)	(2,165,000)
Change in Fair Value on Loans Held for Sale			914,000	(1,000)	$ (1,000)
Net change in:
Trading assets			(68,000)	(333,000)
Loans held for sale			(11,363,000)	846,000
Other assets			(151,830,000)	1,721,000
Increase (Decrease) in Other Operating Liabilities			92,461,000	(5,228,000)
Total adjustments			(37,154,000)	(1,057,000)
Net cash provided by (used in) operating activities			(10,403,000)	34,168,000
Cash flows provided by (used in) investing activities
Increase (Decrease) in Equity Securities, FV-NI			(108,000)	(105,000)
Proceeds from maturities and principal repayments of securities available for sale			31,280,000	11,318,000
Payments to Acquire Debt Securities, Available-for-sale			(30,095,000)
Proceeds from maturities and principal repayments of securities held to maturity			48,183,000	19,003,000
Purchases of securities held to maturity			(84,824,000)	(30,502,000)
Net redemption (purchases) of Federal Home Loan Bank stock			(8,850,000)	8,016,000
Investments in low income housing projects			(5,934,000)	(292,000)
Purchases of life insurance policies			(93,000)	(93,000)
Proceeds from Life Insurance Policy			1,326,000	0
Net increase in loans			(41,283,000)	(70,378,000)
Purchases of bank premises and equipment			(1,749,000)	(3,713,000)
Proceeds from the sale of bank premises and equipment			9,000	13,000
Net cash used in investing activities			(92,138,000)	(66,733,000)
Cash flows provided by (used in) financing activities
Net increase (decrease) in time deposits			(125,396,000)	12,464,000
Net increase in other deposits			394,438,000	24,034,000
Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net			257,826,000	(122,046,000)
Increase Decrease in Federal Home Loan Bank Advances Long Term			(15,000,000)	0
Proceeds from Lines of Credit			0	49,993,000
Proceeds from long-term debt, net of issuance costs			0	74,914,000
RepaymentsOfJuniorSubordinatedDebt			0	(3,093,000)
Proceeds from Issuance of Subordinated Long-term Debt			0	49,556,000
Net proceeds from exercise of stock options			0	(165,000)
Restricted stock awards issued, net of awards surrendered			(1,132,000)	(1,419,000)
Proceeds from shares issued under direct stock purchase plan			560,000	487,000
Payments for shares repurchased under share repurchase program			(73,226,000)	0
Common dividends paid			(15,126,000)	(10,671,000)
Net cash provided by financing activities			422,944,000	74,384,000
Net increase in cash and cash equivalents			320,403,000	41,819,000
Cash and cash equivalents at beginning of year	$ 250,455,000		150,974,000	250,455,000
Cash and cash equivalents at end of period			471,377,000	292,274,000	250,455,000
Supplemental schedule of noncash activities
Net increase in capital commitments relating to low income housing project investments			14,394,000	0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	32,800,000	[1]	$ 2,223,000	$ 2,926,000
Operating Lease, Liability	$ 34,100,000
Deferred Rent Credit					$ 1,300,000

[1] Represents adjustment needed to reflect the opening balance of the Company's Right of Use ("ROU") assets and lease liabilities pursuant to the adoption of Accounting Standards Update 2016-02 effective January 1, 2019. Upon adoption, the Company recognized on its balance sheet ROU assets of approximately $32.8 million, with a corresponding operating lease liability of approximately $34.1 million, with an adjustment to remove the Company's existing deferred rent liability of approximately $1.3 million.