Quarterly report pursuant to Section 13 or 15(d)

Acquisitions Acquisitions (Details)

v3.7.0.1
Acquisitions Acquisitions (Details)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Mar. 31, 2016
USD ($)
Feb. 18, 2016
USD ($)
May 31, 2017
USD ($)
May 31, 2016
USD ($)
May 31, 2017
USD ($)
May 31, 2016
USD ($)
Aug. 31, 2016
acquisition
Mar. 30, 2016
USD ($)
Feb. 17, 2016
USD ($)
Business Acquisition [Line Items]                  
Number of Businesses Acquired | acquisition             2    
Payments to Acquire Businesses, Net of Cash Acquired         $ 0 $ 80,674      
Goodwill, Purchase Accounting Adjustments         1,085        
Net sales     $ 295,427 $ 305,341 820,089 873,641      
Business Acquisition, Pro Forma Revenue     295,427 308,526 820,089 899,535      
Larzep                  
Business Acquisition [Line Items]                  
Business Acquisition, Effective Date of Acquisition   Feb. 17, 2016              
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill                 $ 4,800
Business acquisitions   $ 9,700              
Payments to Acquire Businesses, Net of Cash Acquired   $ 15,900              
Pipeline and Process Services [Member]                  
Business Acquisition [Line Items]                  
Business Acquisition, Effective Date of Acquisition Mar. 30, 2016                
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill               $ 8,700  
Business acquisitions $ 37,400                
Payments to Acquire Businesses, Net of Cash Acquired 65,500                
Goodwill, Purchase Accounting Adjustments $ 1,100                
Fiscal 2016 acquisitions [Member]                  
Business Acquisition [Line Items]                  
Business Combination, Acquisition Related Costs       $ 1,300   $ 2,100      
Net sales     $ 7,300   $ 25,000        
Tradenames | Larzep                  
Business Acquisition [Line Items]                  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill                 1,200
Customer relationships | Larzep                  
Business Acquisition [Line Items]                  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill                 $ 3,600
Customer relationships | Pipeline and Process Services [Member]                  
Business Acquisition [Line Items]                  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill               8,000  
Noncompete Agreements [Member] | Pipeline and Process Services [Member]                  
Business Acquisition [Line Items]                  
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill               $ 700