XML 45 R45.htm IDEA: XBRL DOCUMENT v2.4.1.9
Debt (Details) (USD $)
Dec. 26, 2014
Dec. 27, 2013
Debt Instrument [Line Items]    
Estimated fair value of debt $ 330,000,000us-gaap_LongTermDebtFairValue $ 320,000,000us-gaap_LongTermDebtFairValue
Series A maturing March 2018    
Debt Instrument [Line Items]    
Average Interest Rate 4.00%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesAUnsecuredNoteMember		  
Amount 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesAUnsecuredNoteMember		 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesAUnsecuredNoteMember
Series B maturing March 2023    
Debt Instrument [Line Items]    
Average Interest Rate 5.01%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesBUnsecuredNoteMember		  
Amount 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesBUnsecuredNoteMember		 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesBUnsecuredNoteMember
Series C maturing January 2020    
Debt Instrument [Line Items]    
Average Interest Rate 4.88%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesCUnsecuredNoteMember		  
Amount 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesCUnsecuredNoteMember		 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesCUnsecuredNoteMember
Series D maturing July 2026    
Debt Instrument [Line Items]    
Average Interest Rate 5.35%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesDUnsecuredNoteMember		  
Amount 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesDUnsecuredNoteMember		 75,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_SeriesDUnsecuredNoteMember
Unsecured revolving credit facility maturing June 2019    
Debt Instrument [Line Items]    
Average Interest Rate 1.28%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember		  
Amount 315,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember		 108,370,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember
Notes payable to banks maturing 2015    
Debt Instrument [Line Items]    
Average Interest Rate 0.85%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_NotesPayableToBanksMember		  
Amount 5,016,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_NotesPayableToBanksMember		 9,584,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_NotesPayableToBanksMember
Total debt, including current portion    
Debt Instrument [Line Items]    
Amount $ 620,016,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_DebtTotalMember		 $ 417,954,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= ggg_DebtTotalMember