Periodic payment as a percentage over the principal amount.

No definition available.

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

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

+ References

+ Details

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

- Definition

Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Description of the frequency of periodic payments, which may be presented in a variety of ways (for example, monthly, quarterly, annually).

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The net cash inflow or outflow from cash and cash items that are not available for withdrawal or usage.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=dlng_CreditSuisseAGIIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=dlng_ABNAmroNVMember
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- Details

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Long-Term Debt - Credit Facilities And Senior Notes (Details) - USD ($) $ in Thousands	5 Months Ended	6 Months Ended		12 Months Ended
	May 18, 2017	Jun. 23, 2014	Jun. 19, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 17, 2015	Sep. 15, 2014
Debt Instruments
Weighted average interest rate				5.40%	4.40%	4.50%
Total interest incurred on long-term debt				$ 39,775	$ 32,887	$ 25,926
Debt instrument, remaining borrowing capacity				0	0
Line of credit facility, commitment fee amount				0	2	15
Decrease/ (Increase) in restricted cash				$ 25,000	$ 0	(1,000)
$250.0 Million Senior Unsecured Notes due 2019
Debt Instruments
Principal amount								$ 250,000
Debt Instrument, Maturity Date				Oct. 30, 2019
Senior notes, terms				The Notes bear interest from the date of the original issue until maturity at a rate of 6.25% per year, payable quarterly in arrears on January 30, April 30, July 30 and October 30 of each year.
Senior notes interest rate				6.25%
$340 million Credit Suisse Senior Secured Revolving Credit Facility
Debt Instruments
Principal amount			$ 340,000
Amount repaid		$ 214,100
Debt instrument, description of variable rate basis			LIBOR
Decrease/ (Increase) in restricted cash	$ 25,000
$200 Million Term Loan Facility
Debt Instruments
Principal amount							$ 200,000
Debt instrument, description of variable rate basis							LIBOR
Debt instrument, remaining borrowing capacity						$ 66,700
$480 Term Loan B
Debt Instruments
Principal amount	$ 480,000
Line of credit facility, frequency of payments				quarterly
Debt Instrument, Maturity Date				May 18, 2023
Debt instrument, description of variable rate basis	LIBOR
Debt instrument, payment percentage				0.25%