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Subsequent Events (Details) - Revolving credit facility [Member] - Unsecured debt [Member] - USD ($)
Jul. 21, 2017
Jul. 10, 2017
Jul. 01, 2017
Subsequent Event [Line Items]      
Line of credit maximum borrowing capacity     $ 350,000,000.0
Total borrowings     $ 200,000,000
Subsequent Event [Member]      
Subsequent Event [Line Items]      
Repayments of long-term lines of credit $ 30,000,000 $ 50,000,000