Consolidated Balance Sheets (Unaudited) - USD ($)		Mar. 31, 2021	Dec. 31, 2020
Assets
Cash and due from banks		$ 126,651,000	$ 169,460,000
Interest-earning deposits with banks		1,642,688,000	1,127,176,000
Securities
Trading		3,269,000	2,838,000
Equity Securities, FV-NI		22,419,000	22,107,000
Debt Securities, Available-for-sale		600,213,000	412,860,000
Held to maturity (fair value $820,430 and $752,177)		805,529,000	724,512,000
Total securities		1,431,430,000	1,162,317,000
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group		41,632,000	58,104,000
Loans
Total loans		9,246,691,000	9,392,866,000
Less: allowance for credit losses		(107,549,000)	(113,392,000)
Net loans		9,139,142,000	9,279,474,000
Federal Home Loan Bank stock		10,250,000	10,250,000
Bank premises and equipment, net		115,945,000	116,393,000
Goodwill		506,206,000	506,206,000
Other intangible assets		21,689,000	23,107,000
Cash surrender value of life insurance policies		241,365,000	200,525,000
Other assets		496,916,000	551,289,000
Total assets		13,773,914,000	13,204,301,000
Deposits
Noninterest-bearing demand deposits		4,136,259,000	3,762,306,000
Savings and interest checking accounts		4,242,235,000	4,047,332,000
Money market		2,346,985,000	2,232,903,000
Time certificates of deposit of $100,000 and over		465,182,000	525,424,000
Other time certificates of deposits		402,863,000	425,205,000
Total deposits		11,593,524,000	10,993,170,000
Borrowings
Federal Home Loan Bank borrowings		35,717,000	35,740,000
Long-term Debt		28,099,000	32,773,000
Junior Subordinated Notes		62,851,000	62,851,000
Subordinated debentures (less unamortized debt issuance costs of $280 and $304)		49,720,000	49,696,000
Total borrowings		176,387,000	181,060,000
Other liabilities		288,632,000	327,386,000
Total liabilities		12,058,543,000	11,501,616,000
Commitments and contingencies		$ 0	$ 0
Preferred Stock, Shares Authorized		1,000,000	1,000,000
Preferred Stock, Shares Authorized		$ 0.01	$ 0.01
Stockholders' equity
Preferred stock, $0.01 par value, authorized: 1,000,000 shares, outstanding: none		$ 0	$ 0
Common stock, $0.01 par value, authorized: 75,000,000 shares, issued and outstanding: 33,024,882 shares at March 31, 2021 and 32,965,692 shares at December 31, 2020 (includes 144,790 and 135,205 shares of unvested participating restricted stock awards, respectively)		329,000	328,000
Value of shares held in rabbi trust at cost: 83,629 shares at March 31, 2021 and 84,126 shares at December 31, 2020		(3,080,000)	(3,066,000)
Deferred compensation and other retirement benefit obligations		3,080,000	3,066,000
Additional paid in capital		946,002,000	945,638,000
Retained earnings		741,883,000	716,024,000
Accumulated other comprehensive income, net of tax		27,157,000	40,695,000
Total stockholders’ equity		1,715,371,000	1,702,685,000
Total liabilities and stockholders' equity		13,773,914,000	13,204,301,000
Interest-bearing Deposit Liabilities		100,000	100,000
Debt Securities, Held-to-maturity, Fair Value		820,430,000	752,177,000
Debt Securities, Available-for-sale, Amortized Cost		$ 593,167,000	$ 395,453,000
Shares Held in Rabbi Trust at Cost		83,629	84,126
Common Stock, Shares Authorized		75,000,000	75,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number		144,790	135,205
Common Stock, Shares, Issued		33,024,882	32,965,692
Common Stock, Shares, Outstanding		33,024,882	32,965,692
Preferred Stock, Shares Outstanding		0	0
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Common Class A [Member]
Stockholders' equity
Common Stock, Shares, Outstanding		33,024,882	32,965,692
Long-term Debt [Member]
Stockholders' equity
Unamortized Debt Issuance Expense		$ 26,000	$ 40,000
Subordinated Debt [Member]
Stockholders' equity
Unamortized Debt Issuance Expense		280,000	304,000
Junior Subordinated Debt [Member]
Stockholders' equity
Unamortized Debt Issuance Expense		37,000	37,000
Commercial And Industrial [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		2,086,671,000	2,103,152,000
Total loans		2,086,671,000	2,103,152,000
Commercial Real Estate [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		4,177,617,000	4,173,927,000
Total loans		4,177,617,000	4,173,927,000
Construction Loans [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		516,362,000	553,929,000
Total loans		516,362,000	553,929,000
Small Business [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		174,211,000	175,023,000
Total loans		174,211,000	175,023,000
Residential Real Estate [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		1,241,789,000	1,296,183,000
Total loans		1,241,789,000	1,296,183,000
Home Equity Loan [Member]
Loans
Total loans		1,028,495,000
Consumer Portfolio Segment [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		21,546,000	21,862,000
Total loans	[1]	21,546,000	21,862,000
Senior Lien [Member] | Home Equity Loan [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		610,907,000	633,142,000
Junior Lien [Member] | Home Equity Loan [Member]
Loans
Financing Receivable, before Allowance for Credit Loss		$ 417,588,000	$ 435,648,000

[1] Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances.