XML 46 R35.htm IDEA: XBRL DOCUMENT v3.8.0.1

Note 4 - Derivative Instruments and Hedging Activities - Commodity Forward Contracts (Details) - Not Designated as Hedging Instrument [Member] $ in Thousands	Mar. 31, 2018 USD ($) $ / item
Commodity Contract on February 12, 2018 [Member]
Notional amount | $	$ 3,776
Fixed rate (in USD per Per Share) | $ / item	3.114
Commodity Contract on March 8, 2018 [Member]
Notional amount | $	$ 3,427
Fixed rate (in USD per Per Share) | $ / item	3.109
First Commodity Contract on March 20, 2018 [Member]
Notional amount | $	$ 3,418
Fixed rate (in USD per Per Share) | $ / item	3.101
Second Commodity Contract on March 20, 2018 [Member]
Notional amount | $	$ 1,697
Fixed rate (in USD per Per Share) | $ / item	3.079
Commodity Contract on March 26, 2018 [Member]
Notional amount | $	$ 3,003
Fixed rate (in USD per Per Share) | $ / item	3.027

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The forward price on the price risk forward or futures contract, such as a gas futures contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeForwardPrice
Namespace Prefix:	us-gaap_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=gnrc_CommodityContractOnFebruary122018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=gnrc_CommodityContractOnMarch82018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=gnrc_FirstCommodityContractOnMarch202018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=gnrc_SecondCommodityContractOnMarch202018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=gnrc_CommodityContractOnMarch262018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: