Securities - Amortized Cost and Estimated Fair Value of Securities Available-for-Sale and Held-to-Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	$ 519,297		$ 569,874
Available-for-sale, gross unrealized gains	0		1,275
Available-for-sale, gross unrealized losses	(48,997)		(2,894)
Available-for-sale, fair value	470,300		568,255
Allowance for Credit Losses	0		0
Amortized Cost	1,031,383		1,143,548
Held-to-maturity, gross unrealized gains	512		18,967
Held-to-maturity, gross unrealized losses	(126,469)		(9,771)
Debt securities held-to-maturity	905,426		1,152,744
Allowance for Credit Losses	(1,234)	$ (1,293)	(1,467)	$ (1,503)	$ (1,609)	$ (1,715)
Total, amortized cost	1,550,680		1,713,422
Total, gross unrealized gains	512		20,242
Total, gross unrealized losses	(175,466)		(12,665)
Total, estimated fair value	1,375,726		1,720,999
U.S. government and agency obligations
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	107,198		164,756
Available-for-sale, gross unrealized gains			1,135
Available-for-sale, gross unrealized losses	(8,099)		(471)
Available-for-sale, fair value	99,099		165,420
Allowance for Credit Losses	0		0
Corporate debt securities
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	5,000		5,000
Available-for-sale, gross unrealized gains	0		42
Available-for-sale, gross unrealized losses	(628)		(11)
Available-for-sale, fair value	4,372		5,031
Allowance for Credit Losses	0		0
Amortized Cost	59,000		68,823
Held-to-maturity, gross unrealized gains	403		1,628
Held-to-maturity, gross unrealized losses	(3,135)		(1,279)
Debt securities held-to-maturity	56,268		69,172
Allowance for Credit Losses	(1,135)		(1,343)
Asset-backed securities
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	296,228		298,976
Available-for-sale, gross unrealized gains	0		41
Available-for-sale, gross unrealized losses	(21,355)		(1,489)
Available-for-sale, fair value	274,873		297,528
Allowance for Credit Losses	0		0
Agency commercial
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	110,871		101,142
Available-for-sale, gross unrealized gains	0		57
Available-for-sale, gross unrealized losses	(18,915)		(923)
Available-for-sale, fair value	91,956		100,276
Allowance for Credit Losses	0		0
Amortized Cost	7,440		4,385
Held-to-maturity, gross unrealized gains	6		7
Held-to-maturity, gross unrealized losses	(279)		(44)
Debt securities held-to-maturity	7,167		4,348
Allowance for Credit Losses	0		0
State, municipal and sovereign debt obligations
Securities Financing Transaction [Line Items]
Amortized Cost	263,614		281,389
Held-to-maturity, gross unrealized gains	0		10,185
Held-to-maturity, gross unrealized losses	(31,052)		(1,164)
Debt securities held-to-maturity	232,562		290,410
Allowance for Credit Losses	(63)		(85)
Agency residential
Securities Financing Transaction [Line Items]
Amortized Cost	674,356		756,844
Held-to-maturity, gross unrealized gains	103		6,785
Held-to-maturity, gross unrealized losses	(89,696)		(7,180)
Debt securities held-to-maturity	584,763		756,449
Allowance for Credit Losses	0		0
Non-agency commercial
Securities Financing Transaction [Line Items]
Amortized Cost	26,973		32,107
Held-to-maturity, gross unrealized gains	0		362
Held-to-maturity, gross unrealized losses	(2,307)		(104)
Debt securities held-to-maturity	24,666		32,365
Allowance for Credit Losses	(36)		(39)
Total mortgage-backed securities
Securities Financing Transaction [Line Items]
Amortized Cost	708,769		793,336
Held-to-maturity, gross unrealized gains	109		7,154
Held-to-maturity, gross unrealized losses	(92,282)		(7,328)
Debt securities held-to-maturity	616,596		793,162
Allowance for Credit Losses	$ (36)		$ (39)