Name:	btsg_GeneralAndProfessionalLiabilityInsuranceReservesLongTermLiabilitiesNoncurrent
Namespace Prefix:	btsg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Carrying value as of the balance sheet date of long-term liabilities automobile insurance reserves, noncurrent (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

No definition available.

Name:	btsg_LongTermLiabilitiesAutomobileInsuranceReservesNoncurrent
Namespace Prefix:	btsg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long term liabilities interest rate swaps.

No definition available.

Name:	btsg_LongTermLiabilitiesInterestRateSwaps
Namespace Prefix:	btsg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Carrying value as of the balance sheet date of long-term liabilities noncurrent (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

No definition available.

Name:	btsg_LongTermLiabilitiesNoncurrent
Namespace Prefix:	btsg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

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

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements payable beyond one year (or the operating cycle, if longer).

No definition available.

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

- References

No definition available.

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

Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(24))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

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

Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature. Used to reflect the noncurrent portion of the liabilities (due beyond one year; or beyond one operating cycle if longer).