Debt instrument maturity month year.

No definition available.

Name:	gwrs_DebtInstrumentMaturityMonthYear
Namespace Prefix:	gwrs_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of capital lease obligation due within one year or the normal operating cycle, if longer.

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+ Details

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

- Definition

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal, through the balance sheet date and due to be paid more than one year (or one operating cycle, if longer) after the balance sheet date.

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

- References

No definition available.

+ Details

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

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs classified as current. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of long-term debt and lease obligation, classified as noncurrent.

+ References

+ Details

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

- Definition

Amount of long-term debt and lease obligation, classified as current.

+ References

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwrs_FourPointThreeEightZeroPercentSeriesATwoThousandAndSixteenMaturingJuneTwoThousandAndTwentyEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwrs_FourPointFiveEightZeroPercentSeriesBTwoThousandAndSixteenMaturingJuneTwoThousandAndThirtySixMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwrs_A2012WIFALoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwrs_HarquahalaLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=gwrs_A2017WIFALoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Debt - Schedule of Outstanding Balances and Maturity Dates for Short Term and Long Term Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Mar. 03, 2017	Jun. 24, 2016
Short-term
Capital lease obligations	$ 110		$ 38
Debt issuance costs	0		0
Total debt	117		47
Long-term
Capital lease obligations	251		96
Long-term debt and capital leases	114,664		114,507
BONDS AND NOTES PAYABLE -
Short-term
Short-term debt	7		9
Long-term
Long-term debt, noncurrent	115,018		115,060
BONDS AND NOTES PAYABLE - \| 4.38% Series A 2016, maturing June 2028
Short-term
Short-term debt	0		0
Long-term
Long-term debt, noncurrent	$ 28,750		28,750
Debt instrument, interest rate	4.38%
Debt instrument, maturity date	2028-06
BONDS AND NOTES PAYABLE - \| 4.58% Series B 2016, maturing June 2036
Short-term
Short-term debt	$ 0		0
Long-term
Long-term debt, noncurrent	$ 86,250		86,250
Debt instrument, interest rate	4.58%
Debt instrument, maturity date	2036-06
BONDS AND NOTES PAYABLE - \| 1.20% WIFA Loan, maturing October 2032
Short-term
Short-term debt	$ 0		3
Long-term
Long-term debt, noncurrent	$ 0		39
Debt instrument, interest rate	1.20%	1.20%
Debt instrument, maturity date	2032-10
BONDS AND NOTES PAYABLE - \| 4.65% Harquahala Loan, maturing January 2021
Short-term
Short-term debt	$ 6		5
Long-term
Long-term debt, noncurrent	$ 3		9
Debt instrument, interest rate	4.65%	4.65%
Debt instrument, maturity date	2021-01
BONDS AND NOTES PAYABLE - \| 2017 WIFA Loan [Member]
Short-term
Short-term debt	$ 1		1
Long-term
Long-term debt, noncurrent	$ 15		12
Debt instrument, interest rate	4.60%			4.60%
Debt instrument, maturity date	2037-03
2016 Senior Secured Notes
Long-term
Debt issuance costs	$ (605)		$ (649)
Debt instrument, interest rate					4.55%