Investment Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Dec. 31, 2021
Available for sale debt securities
Amortized Cost	$ 3,673,396,000	$ 3,673,396,000	$ 8,560,733,000
Unrealized Gains	51,000	51,000	24,595,000
Unrealized Losses	(384,287,000)	(384,287,000)	(157,296,000)
Total available-for-sale securities, Fair value,	3,289,160,000	3,289,160,000	8,428,032,000
Held to maturity securities
Amortized Cost	4,406,143,000	4,406,143,000
Unrealized Losses	(445,430,000)	(445,430,000)
Total held to maturity, Fair value,	3,960,713,000	3,960,713,000	0
Available-for-sale investment securities
Accrued interest receivable related to available-for-sale investment securities	8,600,000	8,600,000	14,100,000
Accrued interest receivable related to held to maturity investment securities	7,900,000	7,900,000	0
Reclassification of available for sale securities to held to maturity	417,400,000	4,600,000,000
Other comprehensive income (loss), transfer of securities from available for sale to held to maturity		(372,400,000)
Gain (loss) recognized on reclassification, transfer of securities from available for sale to held to maturity	$ 0	$ 0
Securities held-to-maturity, weighted average life	8 years 1 month 6 days	8 years 1 month 6 days
Collateralized Loan Obligations
Available for sale debt securities
Amortized Cost	$ 249,924,000	$ 249,924,000	105,245,000
Unrealized Gains	51,000	51,000	2,000
Unrealized Losses	(4,455,000)	(4,455,000)
Total available-for-sale securities, Fair value,	245,520,000	245,520,000	105,247,000
U.S. Treasury and government agency debt securities
Available for sale debt securities
Amortized Cost	165,713,000	165,713,000	196,662,000
Unrealized Gains			125,000
Unrealized Losses	(13,191,000)	(13,191,000)	(4,224,000)
Total available-for-sale securities, Fair value,	152,522,000	152,522,000	192,563,000
Held to maturity securities
Amortized Cost	55,069,000	55,069,000
Unrealized Losses	(5,579,000)	(5,579,000)
Total held to maturity, Fair value,	49,490,000	49,490,000
Government-sponsored enterprises debt securities
Available for sale debt securities
Amortized Cost	45,000,000	45,000,000
Unrealized Losses	(674,000)	(674,000)
Total available-for-sale securities, Fair value,	44,326,000	44,326,000
Residential - Government agency
Available for sale debt securities
Amortized Cost	68,969,000	68,969,000	135,764,000
Unrealized Gains			1,791,000
Unrealized Losses	(7,335,000)	(7,335,000)	(291,000)
Total available-for-sale securities, Fair value,	61,634,000	61,634,000	137,264,000
Held to maturity securities
Amortized Cost	46,695,000	46,695,000
Unrealized Losses	(5,228,000)	(5,228,000)
Total held to maturity, Fair value,	41,467,000	41,467,000
Residential - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	1,366,912,000	1,366,912,000	1,496,605,000
Unrealized Gains			6,914,000
Unrealized Losses	(169,071,000)	(169,071,000)	(12,419,000)
Total available-for-sale securities, Fair value,	1,197,841,000	1,197,841,000	1,491,100,000
Held to maturity securities
Amortized Cost	108,145,000	108,145,000
Unrealized Losses	(11,927,000)	(11,927,000)
Total held to maturity, Fair value,	96,218,000	96,218,000
Commercial - Government agency
Available for sale debt securities
Amortized Cost	290,614,000	290,614,000	392,443,000
Unrealized Gains			1,741,000
Unrealized Losses	(39,949,000)	(39,949,000)	(6,521,000)
Total available-for-sale securities, Fair value,	250,665,000	250,665,000	387,663,000
Held to maturity securities
Amortized Cost	30,500,000	30,500,000
Unrealized Losses	(4,784,000)	(4,784,000)
Total held to maturity, Fair value,	25,716,000	25,716,000
Commercial - Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	142,053,000	142,053,000	1,415,511,000
Unrealized Gains			2,646,000
Unrealized Losses	(10,732,000)	(10,732,000)	(48,714,000)
Total available-for-sale securities, Fair value,	131,321,000	131,321,000	1,369,443,000
Held to maturity securities
Amortized Cost	1,159,512,000	1,159,512,000
Unrealized Losses	(135,284,000)	(135,284,000)
Total held to maturity, Fair value,	1,024,228,000	1,024,228,000
Commercial - Non -agency
Available for sale debt securities
Amortized Cost	21,960,000	21,960,000
Unrealized Losses	(290,000)	(290,000)
Total available-for-sale securities, Fair value,	21,670,000	21,670,000
Government agency
Available for sale debt securities
Amortized Cost	769,161,000	769,161,000	2,103,187,000
Unrealized Gains			7,768,000
Unrealized Losses	(74,948,000)	(74,948,000)	(31,432,000)
Total available-for-sale securities, Fair value,	694,213,000	694,213,000	2,079,523,000
Held to maturity securities
Amortized Cost	1,106,231,000	1,106,231,000
Unrealized Losses	(97,089,000)	(97,089,000)
Total held to maturity, Fair value,	1,009,142,000	1,009,142,000
Government-sponsored enterprises
Available for sale debt securities
Amortized Cost	553,090,000	553,090,000	2,671,131,000
Unrealized Gains			3,608,000
Unrealized Losses	(63,642,000)	(63,642,000)	(53,695,000)
Total available-for-sale securities, Fair value,	489,448,000	489,448,000	2,621,044,000
Held to maturity securities
Amortized Cost	1,846,258,000	1,846,258,000
Unrealized Losses	(178,011,000)	(178,011,000)
Total held to maturity, Fair value,	1,668,247,000	1,668,247,000
Debt securities issued by states and political subdivisions
Available for sale debt securities
Amortized Cost			44,185,000
Total available-for-sale securities, Fair value,			$ 44,185,000
Held to maturity securities
Amortized Cost	53,733,000	53,733,000
Unrealized Losses	(7,528,000)	(7,528,000)
Total held to maturity, Fair value,	$ 46,205,000	$ 46,205,000