Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Cash Flows from Operating Activities
Net income	$ 88,978	$ 77,199	$ 164,006	$ 150,583
Adjustments to reconcile net income to net cash provided by operating activities:
Provision/(reversal) for credit losses	2,500	(9,000)	11,143	(22,558)
Provision for losses on other real estate owned			0	47
Deferred tax (benefit)/provision			(1,607)	11,685
Depreciation and amortization			4,575	4,156
Amortization of right-of-use asset			5,038	4,461
Change in operating lease liabilities			(1,976)	710
Net gains on sale and transfer of other real estate owned			(6)	0
Net gains on sale of loans			(1)	(357)
Proceeds from sales of loan			33	6,345
Originations of loans held for sale			0	(5,988)
Loss on sales or disposal of fixed assets			25	55
Amortization on alternative energy partnerships, venture capital and other investments			15,522	22,387
Net gain on sales and calls of securities			(101)	(853)
Amortization/accretion of security premiums/discounts, net			2,231	4,322
Unrealized (gain)/loss on equity securities	1,000	900	(4,919)	3,631
Stock-based compensation and stock issued to officers as compensation			4,216	3,302
Net change in accrued interest receivable and other assets			(37,613)	(4,966)
Net change in other liabilities			18,538	(10,585)
Net cash provided by operating activities			179,104	166,377
Cash Flows from Investing Activities
Purchase of investment securities available-for-sale			(304,445)	(244,567)
Proceeds from repayments, maturities and calls of investment securities available-for-sale			92,789	247,508
Proceeds from sale of investment securities available-for-sale			553	21,102
Net increase in loans			(803,082)	(61,195)
Purchase of premises and equipment			(2,229)	(1,787)
Proceeds from sales of other real estate owned			307	0
Net decrease/(increase) in investment in affordable housing and alternative energy partnerships			1,467	(10,618)
Acquisition, net of cash acquired			(73,882)	0
Net cash (used)/provided for investing activities			(1,088,522)	(49,557)
Cash Flows from Financing Activities
Net (decrease)/increase in deposits			(346,646)	428,291
Advances from Federal Home Loan Bank			75,000	50,000
Repayment of Federal Home Loan Bank borrowings			0	(180,000)
Cash dividends paid			(51,052)	(49,198)
Purchases of treasury stock			(63,484)	(63,529)
Proceeds from shares issued under Dividend Reinvestment Plan			1,873	1,725
Taxes paid related to net share settlement of RSUs			(2,015)	(2,594)
Net cash (used)/provided by financing activities			(386,324)	184,695
(Decrease)/Increase in cash, cash equivalents, and restricted cash			(1,295,742)	301,515
Cash, cash equivalents, and restricted cash, beginning of the period			2,449,704	1,421,078	$ 1,421,078
Cash, cash equivalents, and restricted cash, end of the period	$ 1,153,962	$ 1,722,593	1,153,962	1,722,593	$ 2,449,704
Supplemental disclosure of cash flow information
Interest			26,670	44,669
Income taxes paid			40,181	36,791
Non-cash investing and financing activities:
Net change in unrealized holding loss on securities available-for-sale, net of tax			(72,421)	(4,639)
Net change in unrealized holding gain on cash flow hedge derivatives			4,158	1,702
Loans transferred from held-for-investment to held-for-sale			$ (32)	$ 0