Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Fixed interest rate related to the interest rate derivative.

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The net gain (loss) recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Fair Value Measurement and Interest Rate Swaps (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($) contract
Interest rate swap
Derivative [Line Items]
Number of contracts held \| contract				2
Fair Value of Hedge Assets	$ 3,500,000	$ 3,500,000
Fair value changes recorded in accumulated other comprehensive loss		2,500,000
Ineffectiveness recognized in earnings	0	0
Amount to be reclassified to earnings during the next twelve months		500,000
Derivatives accounted for as hedges \| Forward-starting interest rate swap 1
Derivative [Line Items]
Notional Amount				$ 58,000,000
Fixed Interest Rate				2.1345%
Derivatives accounted for as hedges \| Forward-starting interest rate swap 2
Derivative [Line Items]
Notional Amount				$ 116,000,000
Fixed Interest Rate				2.151%
Cash flow \| Derivatives accounted for as hedges \| Prepaid expenses and other current assets \| Forward-starting interest rate swap 1
Derivative [Line Items]
Fair Value of Hedge Assets	200,000	200,000	$ 0
Cash flow \| Derivatives accounted for as hedges \| Prepaid expenses and other current assets \| Forward-starting interest rate swap 2
Derivative [Line Items]
Fair Value of Hedge Assets	400,000	400,000	0
Cash flow \| Derivatives accounted for as hedges \| Other assets \| Forward-starting interest rate swap 1
Derivative [Line Items]
Fair Value of Hedge Assets	1,000,000	1,000,000	200,000
Cash flow \| Derivatives accounted for as hedges \| Other assets \| Forward-starting interest rate swap 2
Derivative [Line Items]
Fair Value of Hedge Assets	$ 1,900,000	$ 1,900,000	$ 400,000