Debt Securities Available for Sale - Securities Available-for-Sale (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,658,110,000	$ 1,701,379,000
Gross Unrealized Gains	3,240,000	16,943,000
Gross Unrealized (Losses)	(80,709,000)	(14,475,000)
Allowance for Credit Losses	(1,144,000)	0
Debt securities available for sale	1,579,497,000	1,703,847,000
U.S. government and agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	43,185,000	34,711,000
Gross Unrealized Gains	80,000	404,000
Gross Unrealized (Losses)	(1,178,000)	(236,000)
Allowance for Credit Losses	0
Debt securities available for sale	42,087,000	34,879,000
Mortgage-backed securities and collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,488,048,000	1,553,491,000
Gross Unrealized Gains	2,075,000	14,141,000
Gross Unrealized (Losses)	(75,981,000)	(13,273,000)
Allowance for Credit Losses	0
Debt securities available for sale	1,414,142,000	1,554,359,000
Municipal obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,157,000	4,159,000
Gross Unrealized Gains	0	20,000
Gross Unrealized (Losses)	(5,000)	0
Allowance for Credit Losses	(11,000)
Debt securities available for sale	4,141,000	4,179,000
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	122,720,000	109,018,000
Gross Unrealized Gains	1,085,000	2,378,000
Gross Unrealized (Losses)	(3,545,000)	(966,000)
Allowance for Credit Losses	(1,133,000)
Debt securities available for sale	$ 119,127,000	$ 110,430,000

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
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Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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