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Debt (Details) - Credit Facility
 9 Months Ended 12 Months Ended
Sep. 30, 2017
USD ($)
Dec. 31, 2016
USD ($)
Sep. 29, 2017
USD ($)
Apr. 28, 2017
USD ($)
Citibank Credit Facility        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity limit   $ 6,000,000.0    
Letters of credit, amount outstanding $ 2,500,000 $ 2,200,000    
Line of credit, expiration period (in years)   3 years    
Fixed interest rate, short-term   1.25%    
Fixed interest rate, long-term   1.50%    
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity limit 100,000,000.0      
Maximum additional borrowing capacity 150,000,000.0      
Letters of credit, amount outstanding 2,800,000 $ 3,700,000    
Revolving credit facility, amount outstanding 0 $ 0    
Current borrowing capacity $ 30,000,000      
Maximum debt to adjusted EBITDA ratio 2.50      
Minimum EBITDA to interest expense ratio 3.0      
Covenant term, minimum liquidity (no less than)       $ 250,000,000
Wavier fee (as a percent)       0.05%
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Minimum        
Line of Credit Facility [Line Items]        
Commitment fee (as a percent) 0.25%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Maximum        
Line of Credit Facility [Line Items]        
Commitment fee (as a percent) 0.375%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Federal Funds Effective Rate | Interest Option 1, Base Rate        
Line of Credit Facility [Line Items]        
Basis spread on variable rate (as a percent) 0.50%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 1, Base Rate        
Line of Credit Facility [Line Items]        
Basis spread on variable rate (as a percent) 1.00%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 1, Base Rate | Minimum        
Line of Credit Facility [Line Items]        
Additional spread on variable rate (as a percent) 0.50%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 1, Base Rate | Maximum        
Line of Credit Facility [Line Items]        
Additional spread on variable rate (as a percent) 1.50%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 2, Adjusted Eurodollar Rate        
Line of Credit Facility [Line Items]        
Threshold for change in interest payment schedule (in months) 3 months      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 2, Adjusted Eurodollar Rate | Minimum        
Line of Credit Facility [Line Items]        
Basis spread on variable rate (as a percent) 1.50%      
Revolving Credit Facility Maturing August 2018 | Revolving Credit Facility | Eurodollar | Interest Option 2, Adjusted Eurodollar Rate | Maximum        
Line of Credit Facility [Line Items]        
Basis spread on variable rate (as a percent) 2.50%      
Revolving Credit Facility Maturing August 2018 | Letter of Credit        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity limit     $ 20,000,000.0  
Revolving Credit Facility Maturing August 2018 | Swing Line Loan        
Line of Credit Facility [Line Items]        
Maximum borrowing capacity limit     $ 10,000,000.0