Derivative Financial Instruments (Schedule of Cash Flow Hedging Instruments) (Details) - Cash flow hedging - Designated as hedging instrument	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Notional Amount	$ 869,643,000
Fair Value Asset (Liability)	4,614,000
June 2019
Derivative [Line Items]
Notional Amount	200,000,000
Fair Value Asset (Liability)	957,000
July 2019
Derivative [Line Items]
Notional Amount	250,000,000
Fair Value Asset (Liability)	2,196,000
August 2019
Derivative [Line Items]
Notional Amount	275,000,000
Fair Value Asset (Liability)	3,117,000
September 2023
Derivative [Line Items]
Notional Amount	144,643,000
Fair Value Asset (Liability)	$ (1,656,000)