Fair Value - Assets and liabilities measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Assets
Derivative financial instruments	$ 931,400	$ 21,700
Securities available for sale	3,561,929	1,813,134	$ 1,956,047
Liabilities
Derivative financial instruments	935,000	23,500
Government-sponsored entities debt
Assets
Securities available for sale	29,927	40,967	25,941
State and municipal obligations
Assets
Securities available for sale	459,195	188,682	208,415
Corporate securities.
Assets
Securities available for sale	13,652
Significant Other Observable Inputs (Level 2)
Assets
Loans held for sale		87,393
Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	34,578	28,674	30,525
Changes in fair value of assets
Changes in hierarchy classifications of Level 3 liabilities	0
Recurring basis
Assets
Derivative financial instruments	953,036	24,402	16,252
Loans held for sale	456,141	87,393	59,363
Securities available for sale	3,561,929	1,813,134	1,956,047
Mortgage servicing rights	34,578	28,674	30,525
Fair value of Assets, Total	5,005,684	1,953,603	2,062,187
Liabilities
Derivative financial instruments	979,155	43,373	31,273
Recurring basis \| Government-sponsored entities debt
Assets
Securities available for sale	29,927	40,967	25,941
Recurring basis \| State and municipal obligations
Assets
Securities available for sale	459,195	188,682	208,415
Recurring basis \| Mortgage-backed securities
Assets
Securities available for sale	3,059,155	1,583,485	1,721,691
Recurring basis \| Corporate securities.
Assets
Securities available for sale	13,652
Recurring basis \| Significant Other Observable Inputs (Level 2)
Assets
Derivative financial instruments	953,036	24,402	16,252
Loans held for sale	456,141	87,393	59,363
Securities available for sale	3,561,929	1,813,134	1,956,047
Fair value of Assets, Total	4,971,106	1,924,929	2,031,662
Liabilities
Derivative financial instruments	979,155	43,373	31,273
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Government-sponsored entities debt
Assets
Securities available for sale	29,927	40,967	25,941
Recurring basis \| Significant Other Observable Inputs (Level 2) \| State and municipal obligations
Assets
Securities available for sale	459,195	188,682	208,415
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Mortgage-backed securities
Assets
Securities available for sale	3,059,155	1,583,485	1,721,691
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Corporate securities.
Assets
Securities available for sale	13,652
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Mortgage servicing rights	34,578	28,674	30,525
Fair value of Assets, Total	34,578	28,674	$ 30,525
Changes in fair value of assets
Fair value of assets at the beginning of the period	30,525	34,727
Servicing assets that resulted from transfers of financial assets	17,668	4,506
Changes in fair value assets due to valuation inputs or assumptions	(7,540)	(7,218)
Changes in fair value due to decay	6,075	3,341
Fair value of assets at the end of the period	34,578	28,674
Unrealized losses included in accumulated other comprehensive income related to Level 3 financial assets and liabilities	0	$ 0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| CSFL
Changes in fair value of assets
Servicing assets that resulted from transfers of financial assets	$ 3,200

Represents the amount of servicing assets that resulted from transfers of financial assets.

No definition available.

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- Definition

The element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, the element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. The item represents residential mortgage servicing rights as presented on the statement of financial position which are due to the entity as of the balance sheet date.

+ References

No definition available.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

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- Definition

Amount of 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
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

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- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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