Consolidated Statements of Cash Flows - USD ($)		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income		$ 86,173,000	$ 92,049,000	$ 57,603,000
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred loan costs, fees and purchased premiums and discounts		6,063,000	2,121,000	(1,464,000)
Net amortization of premiums and discounts on securities		2,771,000	4,482,000	2,508,000
Net amortization of mortgage servicing rights		233,000	266,000	130,000
Amortization of intangible assets		1,980,000	1,025,000	1,048,000
Depreciation and amortization of office properties and equipment		7,317,000	6,718,000	6,543,000
Amortization of operating lease right-of-use assets		3,821,000	3,633,000	2,641,000
Loss on extinguishment of debt		0	2,851,000	1,158,000
Provision for (reversal of) credit losses	[1]	5,485,000	(9,953,000)	18,447,000
Gain on securities transactions		(210,000)	(2,025,000)	(370,000)
Change in fair value of equity securities		401,000	1,792,000	(767,000)
Gain on securitizations		0	(2,259,000)	(3,544,000)
Gain on sale of loans, net		(178,000)	(8,531,000)	(1,900,000)
Net loss on disposal of office properties and equipment		242,000	95,000	734,000
Loss on write-down of office properties and equipment		0	0	114,000
Loss on write-down of mortgage servicing rights		0	0	75,000
Deferred tax expense		12,769,000	17,709,000	9,738,000
(Increase) decrease in accrued interest receivable		(4,689,000)	2,023,000	(6,685,000)
(Increase) in other assets		(9,884,000)	(22,159,000)	(75,127,000)
Increase in accrued expenses and other liabilities		24,998,000	1,926,000	32,891,000
Income on bank-owned life insurance		(7,393,000)	(5,994,000)	(6,620,000)
Employee stock ownership plan expense		4,850,000	4,052,000	3,161,000
Stock based compensation		7,440,000	8,880,000	8,790,000
(Decrease) increase in deferred compensation obligations under Rabbi Trust		(31,000)	3,000	(60,000)
Net cash provided by operating activities		142,158,000	98,704,000	49,044,000
Cash flows from investing activities:
Proceeds from sales of debt securities available for sale		126,772,000	90,339,000	20,761,000
Proceeds from sales of equity securities		0	1,390,000	0
Proceeds from paydown/maturities/calls of debt securities available for sale		281,959,000	368,249,000	247,908,000
Proceeds from paydown/maturities/calls of debt securities held to maturity		31,151,000	36,103,000	48,640,000
Purchases of debt securities available for sale		(147,181,000)	(667,015,000)	(292,809,000)
Purchases of debt securities held to maturity		(23,298,000)	(203,779,000)	(12,815,000)
Purchases of equity securities		0	(91,000)	0
Proceeds from sales of loans held-for-sale		9,639,000	302,039,000	111,764,000
Proceeds from sales of loans receivable		0	0	35,613,000
Purchases of loans receivable		(8,315,000)	(85,382,000)	0
Net increase in loans receivable		(987,753,000)	(325,917,000)	(80,498,000)
Proceeds from bank-owned life insurance death benefits		1,031,000	5,000	627,000
Proceeds from redemptions of Federal Home Loan Bank stock		77,362,000	28,448,000	50,374,000
Purchases of Federal Home Loan Bank stock		(111,429,000)	(4,798,000)	(22,544,000)
Proceeds from sales of office properties and equipment		1,772,000	1,879,000	0
Additions to office properties and equipment		(7,204,000)	(5,492,000)	(4,624,000)
Net cash acquired in acquisitions		140,769,000	20,417,000	155,248,000
Net cash (used in) provided by investing activities		(614,725,000)	(443,605,000)	257,645,000
Cash flows from financing activities:
Net (decrease) increase in deposits		(71,789,000)	581,475,000	799,548,000
Proceeds from long-term borrowings		335,893,000	37,120,000	90,000,000
Payments from long-term borrowings		(38,725,000)	(306,752,000)	(343,939,000)
Net increase (decrease) in short-term borrowings		446,808,000	(244,027,000)	(376,005,000)
Proceeds from term note		0	29,841,000	0
Payment of subordinated debt		0	0	(16,600,000)
Increase (decrease) in advance payments by borrowers for taxes and insurance		7,648,000	3,406,000	(3,919,000)
Purchase of treasury stock		(93,996,000)	(107,774,000)	(108,166,000)
Exercise of stock options		(393,000)	(25,000)	0
Restricted stock forfeitures		0	0	(24,000)
Repurchase of shares for taxes		(4,614,000)	(357,000)	(174,000)
Net cash provided by (used in) financing activities		580,832,000	(7,093,000)	40,721,000
Net increase (decrease) in cash and cash equivalents		108,265,000	(351,994,000)	347,410,000
Cash and cash equivalents at beginning of year		70,963,000	422,957,000	75,547,000
Cash and cash equivalents at end of year		179,228,000	70,963,000	422,957,000
Cash paid during the period for:
Interest on deposits and borrowings		41,077,000	37,906,000	75,557,000
Income tax payments, net of refunds		15,729,000	16,262,000	10,526,000
Non-cash investing and financing activities:
Transfer of loans receivable to loans held-for-sale		9,461,000	289,362,000	114,171,000
Securitization of loans		0	99,603,000	117,259,000
Initial recognition of operating lease right-of-use asset		0	0	22,218,000
Initial recognition of operating lease liabilities		0	0	23,290,000
Non-cash assets acquired:
Debt securities available for sale		79,024,000	118,017,000	51,479,000
Debt securities held to maturity		0	0	13,418,000
Equity securities		1,075,000	0	1,796,000
Federal Home Loan Bank stock		906,000	3,032,000	2,010,000
Loans receivable		335,501,000	158,912,000	171,593,000
Accrued interest receivable		910,000	867,000	679,000
Office properties and equipment, net		7,296,000	5,934,000	5,774,000
Bank-owned life insurance		13,033,000	8,661,000	17,245,000
Goodwill and intangibles		9,780,000	42,000	0
Other assets		6,356,000	616,000	7,964,000
Total non-cash assets acquired		453,881,000	296,081,000	271,958,000
Liabilities assumed:
Deposits		502,732,000	210,117,000	333,234,000
Borrowings		5,762,000	59,908,000	37,728,000
Advance payments by borrowers for taxes and insurance		1,341,000	495,000	982,000
Accrued expenses and other liabilities		10,568,000	4,822,000	5,400,000
Total liabilities assumed		520,403,000	275,342,000	377,344,000
Net non-cash (liabilities assumed) assets acquired		(66,522,000)	20,739,000	(105,386,000)
Net cash and cash equivalents acquired in acquisitions		$ 140,769,000	$ 20,417,000	$ 155,248,000

[1] (1) The Company adopted ASU 2016-13 as of January 1, 2022. Prior year periods have not been restated.