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Face amount of the debt instrument that is available for borrowing at time the agreement is executed and/or amended.

No definition available.

Name:	ship_DebtInstrumentBorrowingCapacity
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The minimum excess cash in the vessel's operating account as defined in the loan agreement.

No definition available.

Name:	ship_DebtInstrumentExcessCash
Namespace Prefix:	ship_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The number of consecutive, periodic payment installments in which the debt is to be repaid.

No definition available.

Name:	ship_DebtInstrumentNumberOfConsecutivePaymentInstallments
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The number of drawdowns of funds made under the loan agreement.

No definition available.

Name:	ship_DebtInstrumentNumberOfDrawdowns
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Amount of the periodic repayment of any Excess Cash (as defined in the loan agreement) applied to principal.

No definition available.

Name:	ship_DebtInstrumentPeriodicRepaymentOfExcessCashPrincipal
Namespace Prefix:	ship_
Data Type:	xbrli:monetaryItemType
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Minimum liquidity requirements required to be maintained by the borrower under the loan agreement.

No definition available.

Name:	ship_LiquidityRequirements
Namespace Prefix:	ship_
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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Data Type:	num:percentItemType
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Description of the frequency of periodic payments (monthly, quarterly, annual).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02.22)
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
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-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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Data Type:	xbrli:dateItemType
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Amount of the required periodic payments applied to principal.

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Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

No definition available.

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

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromIssuanceOfLongTermDebt
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Period Type:	duration

- References

No definition available.

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