CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Cash and due from banks	$ 268,467	$ 303,373
Interest-bearing deposits in other banks	2,130,615	737,571
Investment securities, at fair value (amortized cost: $7,994,266 as of September 30, 2021 and $5,985,031 as of December 31, 2020)	7,953,727	6,071,415
Loans held for sale	2,052	11,579
Loans and leases	12,834,339	13,279,097
Less: allowance for credit losses	161,246	208,454
Net loans and leases	12,673,093	13,070,643
Premises and equipment, net	317,272	322,401
Accrued interest receivable	64,855	69,626
Bank-owned life insurance	468,968	466,537
Goodwill	995,492	995,492
Mortgage servicing rights	9,107	10,731
Other assets	664,674	603,463
Total assets	25,548,322	22,662,831
Deposits:
Interest-bearing	13,246,579	11,705,609
Noninterest-bearing	8,873,424	7,522,114
Total deposits	22,120,003	19,227,723
Long-term borrowings	200,000	200,010
Retirement benefits payable	144,400	143,373
Other liabilities	372,185	347,621
Total liabilities	22,836,588	19,918,727
Commitments and contingent liabilities (Note 12)
Stockholders' equity
Common stock ($0.01 par value; authorized 300,000,000 shares; issued/outstanding: 140,563,799 / 128,255,570 as of September 30, 2021; issued/outstanding: 140,191,133 / 129,912,272 as of December 31, 2020)	1,406	1,402
Additional paid-in capital	2,524,168	2,514,014
Retained earnings	581,094	473,974
Accumulated other comprehensive (loss) income, net	(61,463)	31,604
Treasury stock (12,308,229 shares as of September 30, 2021 and 10,278,861 shares as of December 31, 2020)	(333,471)	(276,890)
Total stockholders' equity	2,711,734	2,744,104
Total liabilities and stockholders' equity	$ 25,548,322	$ 22,662,831