Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended	18 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Jun. 30, 2023
Cash Flows from Operating Activities
Net income	$ 93,220	$ 88,978	$ 189,227	$ 164,006		$ 189,200
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	9,155	2,500	17,255	11,143
Deferred tax benefit			(9,132)	(1,607)
Depreciation and amortization			4,407	4,575
Amortization of right-of-use asset			4,768	5,038
Change in operating lease liabilities			1,352	(1,976)
Net gains on sale and transfer of other real estate owned			0	(6)
Net gains on sale of loans			0	(1)
Proceeds from sales of loan			0	33
Loss on sales or disposal of fixed assets			6	25
Amortization on alternative energy partnerships, venture capital and other investments			37,340	15,522
Net gain on sales of equity securities			(14)	(101)
Amortization/accretion of security premiums/discounts, net			(2,964)	2,231
Unrealized gain on equity securities	(10,700)	(1,000)	(15,516)	(4,919)
Write-off of AFS debt securities			3,000	0
Stock-based compensation and stock issued to officers as compensation			3,808	4,216
Net change in accrued interest receivable and other assets			(50,971)	(39,269)
Net change in other liabilities			29,281	18,538
Net cash provided by operating activities			211,847	177,448
Cash Flows from Investing Activities
Purchase of investment securities available-for-sale			(180,216)	(304,445)
Proceeds from repayments, maturities and calls of investment securities available-for-sale			173,010	92,789
Proceeds from sale of equity securities			0	553
Benefits received from bank owned life insurance policies			0	1,656
Purchase of Federal Home Loan Bank stock			(15,422)	0
Redemption of Federal Home Loan Bank stock			7,430	0
Net increase in loans			(705,534)	(803,082)
Purchase of premises and equipment			(962)	(2,229)
Proceeds from sales of other real estate owned			0	307
Net (increase)/decrease in investment in affordable housing and alternative energy partnerships			(24,329)	1,467
Acquisition, net of cash acquired			0	(73,882)
Net cash used for investing activities			(746,023)	(1,086,866)
Cash Flows from Financing Activities
Increase/(decrease) in deposits			591,689	(346,646)
Net Advances from Federal Home Loan Bank			330,000	75,000
Cash dividends paid			(49,266)	(51,052)
Purchases of treasury stock			(16,692)	(63,484)
Proceeds from shares issued under Dividend Reinvestment Plan			1,835	1,873		1,800
Taxes paid related to net share settlement of RSUs			(3,527)	(2,015)
Net cash provided/(used) by financing activities			854,039	(386,324)
Increase/(decrease) in cash, cash equivalents, and restricted cash			319,863	(1,295,742)
Cash, cash equivalents, and restricted cash, beginning of the period			1,162,402	2,449,704	$ 2,449,704	2,449,704
Cash, cash equivalents, and restricted cash, end of the period	$ 1,482,265	$ 1,153,962	1,482,265	1,153,962	$ 1,162,402	$ 1,482,265
Supplemental disclosure of cash flow information
Interest			203,611	26,670
Income taxes paid			48,712	40,181
Non-cash investing and financing activities:
Net change in unrealized holding gain/(loss) on securities available-for-sale, net of tax			4,128	(72,421)
Net change in unrealized holding (loss)/gain on cash flow hedge derivatives			(882)	4,158
Loans transferred from held-for-investment to held-for-sale			$ 0	$ 32