Name:	sncy_CaresActEmployeeRetentionCredit
Namespace Prefix:	sncy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of grants provided under CARES Act, recognized during period.

No definition available.

Name:	sncy_CaresActGrantsRecognized
Namespace Prefix:	sncy_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The cash inflow from grants received under the CARES Act.

No definition available.

Name:	sncy_ProceedsFromGovernmentGrants
Namespace Prefix:	sncy_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Carrying amount as of the balance sheet date of amounts due under the terms of governmental, corporate, or foundation grants.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

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

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.

No definition available.