Fair Value of Assets and Liabilities - Carrying Amount and Estimated Fair Value of Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Carrying Amount
Financial assets
Cash and cash equivalents	$ 1,529,534	$ 401,995
Debt securities, held-to-maturity	3,664,393	3,715,052
Loans receivable, net of ACL	15,332,008	15,064,529
Total financial assets	20,525,935	19,181,576
Financial liabilities
Term deposits	1,155,494	880,589
FHLB advances	335,000	1,800,000
FRB Bank Term Funding	2,740,000
Repurchase agreements and other borrowed funds	1,267,508	1,023,209
Subordinated debentures	132,822	132,782
Total financial liabilities	5,630,824	3,836,580
Estimated Fair Value | Level 1
Financial assets
Cash and cash equivalents	1,529,534	401,995
Debt securities, held-to-maturity	0	0
Loans receivable, net of ACL	0	0
Total financial assets	1,529,534	401,995
Financial liabilities
Term deposits	0	0
FHLB advances	0	0
FRB Bank Term Funding
Repurchase agreements and other borrowed funds	0	0
Subordinated debentures	0	0
Total financial liabilities	0	0
Estimated Fair Value | Level 2
Financial assets
Cash and cash equivalents	0	0
Debt securities, held-to-maturity	3,292,753	3,274,792
Loans receivable, net of ACL	0	0
Total financial assets	3,292,753	3,274,792
Financial liabilities
Term deposits	1,156,303	874,850
FHLB advances	335,000	1,799,936
FRB Bank Term Funding	2,730,300
Repurchase agreements and other borrowed funds	1,267,508	1,023,209
Subordinated debentures	113,358	122,549
Total financial liabilities	5,602,469	3,820,544
Estimated Fair Value | Level 3
Financial assets
Cash and cash equivalents	0	0
Debt securities, held-to-maturity	0	0
Loans receivable, net of ACL	15,063,785	14,806,354
Total financial assets	15,063,785	14,806,354
Financial liabilities
Term deposits	0	0
FHLB advances	0	0
FRB Bank Term Funding
Repurchase agreements and other borrowed funds	0	0
Subordinated debentures	0	0
Total financial liabilities	$ 0	$ 0