Derivative Instruments And Hedging Activities Interest Rate Swaps (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Interest expense	$ 34,264	$ 32,324	$ 70,911	$ 65,047

Amount of the cost of borrowed funds accounted for as interest expense.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration