Business acquisition, percentage of noncontrolling interest acquired.

No definition available.

Name:	csfl_BusinessAcquisitionPercentageOfNoncontrollingInterestAcquired
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Business acquisition percentage of voting Interests acquired by subsidiary.

+ References

No definition available.

+ Details

Name:	csfl_BusinessAcquisitionPercentageOfVotingInterestsAcquiredBySubsidiary
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Business combination common stock shares exchanged per share of acquire common stock.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationCommonStockSharesExchangedPerShareOfAcquireCommonStock
Namespace Prefix:	csfl_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Business combination, number of troubled debt restructure acquired.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationNumberOfTroubledDebtRestructureAcquired
Namespace Prefix:	csfl_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of core deposit intangible acquired at the acquisition date.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCoreDepositIntangible
Namespace Prefix:	csfl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business combination recognized identifiable assets acquired and liabilities assumed loans adjustment in fair value.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansAdjustmentInFairValue
Namespace Prefix:	csfl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business combination recognized identifiable assets acquired and liabilities assumed loans adjustment in fair value percentage.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansAdjustmentInFairValuePercentage
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Business combination recognized identifiable assets acquired and liabilities assumed loans fair value.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansFairValue
Namespace Prefix:	csfl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business combination recognized identifiable assets acquired and liabilities assumed purchased credit impaired loans.

+ References

No definition available.

+ Details

Name:	csfl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPurchasedCreditImpairedLoans
Namespace Prefix:	csfl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The period of time from the date of acquisition allotted to determine the closing date fair values of certain assets acquired pursuant to the business combination.

+ References

No definition available.

+ Details

Name:	csfl_FairValueEstimatesDeterminationPeriod
Namespace Prefix:	csfl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage increase decrease in assets.

+ References

No definition available.

+ Details

Name:	csfl_PercentageIncreaseDecreaseInAssets
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage increase decrease in deposits.

+ References

No definition available.

+ Details

Name:	csfl_PercentageIncreaseDecreaseInDeposits
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of loan acquired.

+ References

No definition available.

+ Details

Name:	csfl_PercentageOfLoanAcquired
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of outstanding stock acquired.

+ References

No definition available.

+ Details

Name:	csfl_PercentageOfOutstandingStockAcquired
Namespace Prefix:	csfl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

+ Details

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

- Definition

Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e848-128460

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e845-128460

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460

+ Details

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6578-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

+ Details

Name:	us-gaap_Deposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

+ Details

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

- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=csfl_NationalCommerceCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EquityInterestIssuedOrIssuableByTypeAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=csfl_CBIHoldingCompanyLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=csfl_SouthStateCorporationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Business Combinations - Additional Information (Detail) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 01, 2019 USD ($) SecurityLoan	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill on the acquisition		$ 1,204,417			$ 1,204,417
Per share exchange ratio		0.3001
Loans at fair value	$ 3,327,850
Estimated discount on loans acquired	$ 61,384
Estimated discount to outstanding principal balance	1.80%
Percentage of loan acquired						39.90%
Purchased credit impaired loans	$ 18,616
Total assets		$ 18,596,292	$ 12,587,637		17,142,025
Deposits		14,121,499			$ 13,136,392
National Commerce Corporation [Member]
Business Acquisition [Line Items]
Effective date of acquisition				Apr. 01, 2019
Total purchase consideration	$ 831,696
Increase in total assets	36.00%
Increase in total deposits	37.00%
Merger and acquisition related expenses		$ (25)	$ 1,264
Goodwill on the acquisition	$ 401,537
Determination period for fair value estimates	1 year
Per share exchange ratio	1.650
Purchased credit impaired loans	$ 18,616
Number of troubled debt restructure acquired \| SecurityLoan	0
Core deposit intangible	$ 39,900
National Commerce Corporation [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life		10 years
National Commerce Corporation [Member] \| Common Stock [Member]
Business Acquisition [Line Items]
Percentage of outstanding stock acquired	100.00%
CBI Holding Company LLC [Member]
Business Acquisition [Line Items]
Percentage of controlling interest acquired by subsidiary				70.00%
Percentage of noncontrolling interest acquired				30.00%
Total purchase consideration				$ 11,400
South State Corporation [Member]
Business Acquisition [Line Items]
Total assets		$ 16,642,911
Deposits		12,344,547
Loans and Leases Receivable, Net Amount		$ 11,506,890