Summary of Significant Accounting Policies - Narrative (Details)
 3 Months Ended
Mar. 31, 2019
USD ($)
segment
renewal_option
Mar. 31, 2018
USD ($)
Jan. 01, 2019
USD ($)
Dec. 31, 2018
USD ($)
Summary Of Significant Accounting Policies [Line Items]        
Net assets $ 5,158,857,000     $ 5,096,316,000
Net liabilities $ 2,340,221,000     2,294,567,000
Number of segments | segment 1      
Number of renewal options (or more) | renewal_option 1      
Option to terminate, percentage (less than) 1.00%      
Option to purchase, percentage (less than) 6.00%      
Rent escalators adjustment period 1 year      
Reserves for uncollectible amounts $ 5,400,000     4,900,000
Accounts receivable 11,900,000     12,400,000
Reserve for losses 2,000,000     1,100,000
Deferred rental revenue receivables 73,000,000     69,400,000
Goodwill impairment 0 $ 0    
Provision for income taxes 0      
Bad debt expense 900,000      
Operating lease, right-of-use assets 6,100,000      
Operating lease, liabilities 8,285,000      
Special Purpose Entity        
Summary Of Significant Accounting Policies [Line Items]        
Net assets 880,000,000     900,000,000
Net liabilities 470,000,000     480,000,000
Spirit Realty, L.P.        
Summary Of Significant Accounting Policies [Line Items]        
Net assets 5,158,857,000     5,096,316,000
Net liabilities 2,340,221,000     $ 2,294,567,000
Provision for income taxes $ 0      
Accounting Standards Update 2016-02        
Summary Of Significant Accounting Policies [Line Items]        
Operating lease, right-of-use assets     $ 6,400,000  
Operating lease, liabilities     $ 8,600,000  
Minimum        
Summary Of Significant Accounting Policies [Line Items]        
Renewal term 5 years      
Maximum        
Summary Of Significant Accounting Policies [Line Items]        
Renewal term 10 years      
Walgreen Co.        
Summary Of Significant Accounting Policies [Line Items]        
Lease term 50 years      
Termination period 5 years