Derivatives - Narrative (Details) - Interest rate contracts - USD ($)	1 Months Ended		3 Months Ended
	Nov. 30, 2018	Apr. 30, 2017	Dec. 31, 2018
Derivative [Line Items]
Term of derivative contract	5 years	3 years
Notional amount of derivative	$ 139,000,000.0	$ 60,000,000.0
Derivative fixed interest rate (as a percent)	3.09%	1.58%
Derivative quarterly reduction amount			$ 5,000,000.0