Consolidated Statements of Cash Flows	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Cash flow from operating activities
Net income	$ 165,175,000	$ 121,622,000	$ 87,204,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	19,439,000	15,629,000	15,760,000
Change In Unamortized Net Loan Costs And Premiums	(10,086,000)	365,000	(79,000)
Provision for loan losses	6,000,000	4,775,000	2,950,000
Deferred income tax expense (benefit)	10,594,000	(4,497,000)	9,211,000
Tax Expense related to a change in tax law	0	0	466,000
Equity Securities, FV-NI, Gain (Loss)	(1,566,000)	1,225,000
Loss on write-down of investments in securities available for sale	1,462,000		(3,000)
Net gain on bank premises and equipment	(474,000)	(1,126,000)	(108,000)
Net loss on other real estate owned and foreclosed assets	401,000	112,000	288,000
Realized gain on sale leaseback transaction	(578,000)	(730,000)	(1,034,000)
Stock based compensation	4,403,000	4,225,000	3,333,000
Increase in cash surrender value of life insurance policies	(5,013,000)	(4,060,000)	(4,127,000)
Gain Realized on Life Insurance Policies	(434,000)	(1,463,000)	0
Operating Lease, Payments	(10,669,000)	0	0
Change in Fair Value on Loans Held for Sale	(822,000)	51,000	113,000
Net change in:
Trading assets	(675,000)	(180,000)	(520,000)
Loans held for sale	59,932,000	(1,714,000)	1,258,000
Other assets	(39,850,000)	503,000	20,022,000
Other liabilities	19,283,000	7,100,000	(3,825,000)
Total adjustments	51,347,000	20,215,000	43,705,000
Net cash provided by operating activities	216,522,000	141,837,000	130,909,000
Cash flows provided by (used) in investing activities
Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment	1,461,000	5,752,000
Increase (Decrease) in Equity Securities, FV-NI	(711,000)	(6,315,000)	0
Proceeds from Sale of Available-for-sale Securities, Equity			0
Proceeds from Sale of Debt Securities, Available-for-sale	45,863,000		1,027,000
Proceeds from maturities and principal repayments of securities available for sale	51,104,000	82,418,000	54,191,000
Payments to Acquire Debt Securities, Available-for-sale	(68,677,000)	(78,990,000)	(140,885,000)
Proceeds from maturities and principal repayments of securities held to maturity	126,991,000	82,355,000	78,757,000
Purchases of securities held to maturity	(59,967,000)	(195,538,000)	(89,033,000)
Net redemption (purchases) of Federal Home Loan Bank stock	18,896,000	(2,376,000)	386,000
Investments in low income housing projects	(10,052,000)	(3,434,000)	(7,645,000)
Purchases of life insurance policies	(163,000)	(164,000)	(164,000)
Proceeds from Life Insurance Policy	3,162,000	2,850,000	0
Net (increase) decrease in loans	27,816,000	(258,633,000)	(204,702,000)
Cash Acquired in Excess of Payments to Acquire Business			6,289,000
Net cash acquired (paid) in business combinations	(105,264,000)	(6,906,000)
Purchases of bank premises and equipment	(16,583,000)	(11,106,000)	(25,080,000)
Proceeds from the sale of bank premises and equipment	3,796,000	2,189,000	6,306,000
Proceeds from the sale of other real estate owned and foreclosed assets	2,488,000	387,000	3,784,000
Net cash provided by (used in) investing activities	20,160,000	(387,511,000)	(316,769,000)
Cash flows provided by (used in) financing activities
Net decrease in time deposits	(45,272,000)	(1,430,000)	(19,509,000)
Net increase (decrease) in other deposits	(160,637,000)	280,017,000	177,241,000
Net proceeds from (repayments of) short-term Federal Home Loan Bank borrowings	(132,046,000)	67,046,000
Repayments of long-term Federal Home Loan Bank borrowings	(25,000,000)	(2,475,000)	0
Net decrease in customer repurchase agreements		(21,503,000)	(14,234,000)
Proceeds from Lines of Credit	49,980,000	0	0
Repayments of Lines of Credit	(49,980,000)	0	0
Proceeds from Debt, Net of Issuance Costs	74,867,000	0	0
RepaymentsOfJuniorSubordinatedDebt	(13,329,000)	0	0
Proceeds from Issuance of Subordinated Long-term Debt	49,526,000	0	0
Repayments of Subordinated Debt	(34,767,000)	0	0
Net proceeds from exercise of stock options	281,000	184,000	214,000
Restricted stock awards issued, net of awards surrendered	(1,463,000)	(1,371,000)	(1,422,000)
Proceeds from shares issued under the direct stock purchase plan	4,951,000	2,712,000	1,636,000
Common dividends paid	(53,274,000)	(40,167,000)	(34,045,000)
Net cash provided by (used in) financing activities	(336,163,000)	283,013,000	109,881,000
Net increase (decrease) in cash and cash equivalents	(99,481,000)	37,339,000	(75,979,000)
Cash and cash equivalents at beginning of year	250,455,000	213,116,000	289,095,000
Cash and cash equivalents at end of period	150,974,000	250,455,000	213,116,000
Supplemental schedule of noncash investing and financing activities
Interest Paid, Excluding Capitalized Interest, Operating Activities	49,704,000	25,337,000	18,626,000
Income taxes	39,575,000	27,809,000	32,865,000
Transfer of loans to other real estate owned and foreclosed assets			511,000
Capital commitment relating to Low Income Housing Project investments, noncash	36,543,000	2,833,000	20,000
Transfer of customer repurchase agreements to deposits noncash	0	141,176,000	0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	14,951,000	0	0
Operating Lease, Right-of-Use Asset	56,600,000
Operating Lease, Liability	58,302,000	0
Deferred Rent Credit		1,300,000
In conjunction with the Company's acquisitions, assets were acquired and liabilities were assumed as follows
Common stock issued for acquisition	$ 499,693,000	42,474,000	23,468,000
Fair value of assets acquired, net of cash acquired		362,286,000	179,252,000
Fair value of liabilities assumed		$ 312,906,000	$ 162,073,000