Securities - Amortized Cost and Estimated Fair Value of Securities Available-for-Sale and Held-to-Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	$ 543,761		$ 569,874
Available-for-sale, gross unrealized gains	1		1,275
Available-for-sale, gross unrealized losses	(36,486)		(2,894)
Available-for-sale, fair value	507,276		568,255
Allowance for Credit Losses	0		0
Amortized Cost	1,071,911		1,143,548
Held-to-maturity, gross unrealized gains	918		18,967
Held-to-maturity, gross unrealized losses	(85,297)		(9,771)
Debt securities held-to-maturity	987,532		1,152,744
Allowance for Credit Losses	(1,293)	$ (1,380)	(1,467)	$ (1,609)	$ (1,717)	$ (1,715)
Total, amortized cost	1,615,672		1,713,422
Total, gross unrealized gains	919		20,242
Total, gross unrealized losses	(121,783)		(12,665)
Total, estimated fair value	1,494,808		1,720,999
U.S. government and agency obligations
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	131,394		164,756
Available-for-sale, gross unrealized gains	1		1,135
Available-for-sale, gross unrealized losses	(5,591)		(471)
Available-for-sale, fair value	125,804		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	(410)		(11)
Available-for-sale, fair value	4,590		5,031
Allowance for Credit Losses	0		0
Amortized Cost	62,212		68,823
Held-to-maturity, gross unrealized gains	555		1,628
Held-to-maturity, gross unrealized losses	(3,247)		(1,279)
Debt securities held-to-maturity	59,520		69,172
Allowance for Credit Losses	(972)		(1,343)
Asset-backed securities
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	296,232		298,976
Available-for-sale, gross unrealized gains	0		41
Available-for-sale, gross unrealized losses	(17,251)		(1,489)
Available-for-sale, fair value	278,981		297,528
Allowance for Credit Losses	0		0
Agency commercial
Securities Financing Transaction [Line Items]
Available-for-sale, amortized cost	111,135		101,142
Available-for-sale, gross unrealized gains	0		57
Available-for-sale, gross unrealized losses	(13,234)		(923)
Available-for-sale, fair value	97,901		100,276
Allowance for Credit Losses	0		0
Amortized Cost	7,741		4,385
Held-to-maturity, gross unrealized gains	36		7
Held-to-maturity, gross unrealized losses	(35)		(44)
Debt securities held-to-maturity	7,742		4,348
Allowance for Credit Losses	0		0
State, municipal and sovereign debt obligations
Securities Financing Transaction [Line Items]
Amortized Cost	268,473		281,389
Held-to-maturity, gross unrealized gains	109		10,185
Held-to-maturity, gross unrealized losses	(21,443)		(1,164)
Debt securities held-to-maturity	247,139		290,410
Allowance for Credit Losses	(291)		(85)
Agency residential
Securities Financing Transaction [Line Items]
Amortized Cost	701,478		756,844
Held-to-maturity, gross unrealized gains	218		6,785
Held-to-maturity, gross unrealized losses	(58,953)		(7,180)
Debt securities held-to-maturity	642,743		756,449
Allowance for Credit Losses	0		0
Non-agency commercial
Securities Financing Transaction [Line Items]
Amortized Cost	32,007		32,107
Held-to-maturity, gross unrealized gains	0		362
Held-to-maturity, gross unrealized losses	(1,619)		(104)
Debt securities held-to-maturity	30,388		32,365
Allowance for Credit Losses	(30)		(39)
Total mortgage-backed securities
Securities Financing Transaction [Line Items]
Amortized Cost	741,226		793,336
Held-to-maturity, gross unrealized gains	254		7,154
Held-to-maturity, gross unrealized losses	(60,607)		(7,328)
Debt securities held-to-maturity	680,873		793,162
Allowance for Credit Losses	$ (30)		$ (39)