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Derivatives and Hedging Activities - Narrative (Details) - USD ($)
12 Months Ended
Sep. 06, 2017
Dec. 31, 2017
Dec. 31, 2016
Sep. 22, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]        
Payment to terminate existing interest rate swap contract $ 1,100,000      
Derivative liability, notional amount   $ 433,000,000 $ 153,600,000 $ 100,000,000
Derivative, fixed interest rate       1.94%
Hedge ineffectiveness   $ 0 $ 0