XML 60 R44.htm IDEA: XBRL DOCUMENT v3.8.0.1
Commitments and Contingencies - Build to Suit (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2017
USD ($)
phase
Dec. 31, 2016
USD ($)
Dec. 31, 2014
USD ($)
Jun. 30, 2013
USD ($)
Commitments and Contingencies Disclosure [Abstract]        
Financing obligation number of phases | phase 2      
Financing obligation, lessor committed fundings phase 1 $ 11,800      
Financing obligation, lessor committed fundings phase 2 11,100      
Debt Instrument [Line Items]        
Capital leased assets 37,274 $ 38,350    
Property, Plant and Equipment [Line Items]        
Property and equipment, gross $ 56,079 55,619    
Financing obligation, purchase option period 3 years      
Buildings        
Debt Instrument [Line Items]        
Capital leased assets $ 36,608 36,603    
Property, Plant and Equipment [Line Items]        
Property and equipment, gross $ 36,608 $ 36,603 $ 19,900 $ 17,100
Financing Lease Obligation        
Debt Instrument [Line Items]        
Capital leased assets     $ 11,100 $ 11,800