Investment Securities - Age of Unrealized Losses and Fair Value of Related Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value
Less than Twelve Months	$ 2,567,577	$ 1,440,435
More than Twelve Months	565,562	242,949
Total	3,133,139	1,683,384
Unrealized Losses
Less than Twelve Months	(235,020)	(22,830)
More than Twelve Months	(93,543)	(11,242)
Total	(328,563)	(34,072)
U.S. Treasury securities
Fair Value
Less than Twelve Months	34,914
More than Twelve Months	0
Total	34,914
Unrealized Losses
Less than Twelve Months	(29)
More than Twelve Months	0
Total	(29)	0
U.S. government agency securities
Fair Value
Less than Twelve Months	220,737
More than Twelve Months	0
Total	220,737
Unrealized Losses
Less than Twelve Months	(16,495)
More than Twelve Months	0
Total	(16,495)	0
Obligations of states and state agencies
Fair Value
Less than Twelve Months	61,460	17,000
More than Twelve Months	9,610	5,517
Total	71,070	22,517
Unrealized Losses
Less than Twelve Months	(1,466)	(254)
More than Twelve Months	(1,002)	(58)
Total	(2,468)	(312)
Municipal bonds
Fair Value
Less than Twelve Months	251,294	9,403
More than Twelve Months	1,311	0
Total	252,605	9,403
Unrealized Losses
Less than Twelve Months	(16,606)	(87)
More than Twelve Months	(101)	0
Total	(16,707)	(87)
Obligations of states and political subdivisions
Fair Value
Less than Twelve Months	312,754	26,403
More than Twelve Months	10,921	5,517
Total	323,675	31,920
Unrealized Losses
Less than Twelve Months	(18,072)	(341)
More than Twelve Months	(1,103)	(58)
Total	(19,175)	(399)
Residential mortgage-backed securities
Fair Value
Less than Twelve Months	1,931,648	1,381,405
More than Twelve Months	524,191	206,520
Total	2,455,839	1,587,925
Unrealized Losses
Less than Twelve Months	(197,148)	(22,365)
More than Twelve Months	(86,857)	(6,075)
Total	(284,005)	(28,440)
Trust preferred securities
Fair Value
Less than Twelve Months	0	0
More than Twelve Months	30,450	30,912
Total	30,450	30,912
Unrealized Losses
Less than Twelve Months	0	0
More than Twelve Months	(5,583)	(5,109)
Total	(5,583)	(5,109)
Corporate and other debt securities
Fair Value
Less than Twelve Months	67,524	32,627
More than Twelve Months	0	0
Total	67,524	32,627
Unrealized Losses
Less than Twelve Months	(3,276)	(124)
More than Twelve Months	0	0
Total	$ (3,276)	$ (124)

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=SL120269820-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27337-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValueAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27337-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_StateAndLocalJurisdictionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: