Anticipated payment to the postretirement plans participants for the next fiscal year for non-qualified trusts.

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- Definition

Defined Benefit Plan, Lump-sum Payment Recognized as Settlement Gain (Loss), Minimum Threshold

+ References

No definition available.

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- Definition

Reflects the upper limit on age eligibility, post early retirement, when medical insurance is available to retiree.

+ References

No definition available.

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- Definition

Lump Sum Payments Recognized As Settlements

+ References

No definition available.

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- Definition

The amortization period for transition obligation not yet in postretirement benefit costs.

+ References

No definition available.

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- Definition

Amount of contributions made by the employer to defined benefit plans.

+ References

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-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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- Definition

Amount of net gain (loss) recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include, but are not limited to, lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contracts to cover vested benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
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- Definition

The amount of increase related to special termination benefits offered to and accepted by employees in connection with their termination of employment that are only offered for a short period of time. A situation involving termination benefits may also involve a curtailment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Termination Benefits
-URI http://asc.fasb.org/extlink&oid=6526498

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- 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.

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- Definition

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

+ References

No definition available.

+ Details

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PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($)	3 Months Ended			6 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Extent of lump-sum payments recognized, percentage				100.00%
Medical insurance available until age is reached after early retirement				65 years
Amortization period for transition obligation excluded from postretirement benefit cost (in years)				20 years
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Gain on lump-sum settlements	$ 2,200,000		$ 0	$ 2,200,000	$ 0
Special termination benefits	0	$ 1,600,000	0	1,600,000	0
Pension Plans \| Laclede Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions made by employer				11,000,000
Anticipated contributions to pension plans for qualified trust				15,000,000
Pension Plans \| Alagasco
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Lump-sum payments recognized as settlements	11,800,000
Gain on lump-sum settlements	2,200,000		0	2,200,000	0
Contributions made by employer				0
Anticipated contributions to pension plans for qualified trust				0
Nonqualified Pension Plans \| Laclede Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions made by employer				300,000
Anticipated contributions to pension plans for qualified trust				200,000
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Anticipated contributions to pension plans for qualified trust				7,100,000
Special termination benefits	$ 0	$ 2,600,000	$ 0	2,600,000	$ 0
Anticipated payment directly to participants in postretirement plan				300,000
Postretirement Plans \| Laclede Gas
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions made by employer				$ 7,200,000