Financing receivable, allowance for credit losses, purchased credit impaired.

No definition available.

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Namespace Prefix:	cstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Financing receivable, purchased credit impaired.

+ References

No definition available.

+ Details

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Namespace Prefix:	cstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

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

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI https://asc.fasb.org/extlink&oid=122038336&loc=d3e74567-122707

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI https://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

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

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ 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 https://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

+ Details

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

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=cstr_ConsumerRealEstatePortfolioSegmentMember
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Data Type:	na
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Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=cstr_ConstructionAndLandDevelopmentPortfolioSegmentMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Loans and Allowance for Loan Losses - Summary of Breakdown of Allowance for Loan Losses and Loan Portfolio by Loan Category (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Allowance for Loan Losses:
Collectively evaluated for impairment	$ 21,603		$ 21,307
Individually evaluated for impairment			200
Purchased credit impaired	81		191
Allowance for Loan Losses, Ending Balance	21,684	$ 20,857	21,698	$ 22,754	$ 23,877	$ 23,245
Loans:
Collectively evaluated for impairment	2,218,727		1,944,165
Individually evaluated for impairment	297		2,343
Purchased credit impaired	15,809		19,261
Total	2,234,833		1,965,769
Commercial real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	7,149		7,075
Purchased credit impaired			49
Allowance for Loan Losses, Ending Balance	7,149	6,987	7,124	7,915	7,688	7,349
Loans:
Collectively evaluated for impairment	1,024,370		820,204
Individually evaluated for impairment			1,151
Purchased credit impaired	3,701		3,929
Total	1,028,071		825,284
Consumer real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	2,555		2,211
Individually evaluated for impairment			200
Purchased credit impaired			1
Allowance for Loan Losses, Ending Balance	2,555	2,214	2,412	1,730	1,679	1,831
Loans:
Collectively evaluated for impairment	348,326		313,849
Individually evaluated for impairment	200		909
Purchased credit impaired	9,323		11,654
Total	357,849		326,412
Construction and land development
Allowance for Loan Losses:
Collectively evaluated for impairment	3,271		3,769
Allowance for Loan Losses, Ending Balance	3,271	3,308	3,769	3,871	3,363	3,476
Loans:
Collectively evaluated for impairment	205,480		214,209
Individually evaluated for impairment	9		10
Purchased credit impaired	84		91
Total	205,573		214,310
Commercial and industrial
Allowance for Loan Losses:
Collectively evaluated for impairment	7,435		7,376
Purchased credit impaired	29		65
Allowance for Loan Losses, Ending Balance	7,464	7,206	7,441	8,401	10,212	9,708
Loans:
Collectively evaluated for impairment	509,042		495,114
Individually evaluated for impairment	79		250
Purchased credit impaired	1,866		2,251
Total	510,987		497,615
Consumer
Allowance for Loan Losses:
Collectively evaluated for impairment	446		321
Purchased credit impaired	52		76
Allowance for Loan Losses, Ending Balance	498	381	397	356	333	305
Loans:
Collectively evaluated for impairment	52,576		45,754
Individually evaluated for impairment	9		23
Purchased credit impaired	642		1,034
Total	53,227		46,811
Other
Allowance for Loan Losses:
Collectively evaluated for impairment	747		555
Allowance for Loan Losses, Ending Balance	747	$ 761	555	$ 481	$ 602	$ 576
Loans:
Collectively evaluated for impairment	78,933		55,035
Purchased credit impaired	193		302
Total	$ 79,126		$ 55,337