Derivative Financial Instruments - Effect of Cash Flow Hedging on AOCI (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]
Gain (Loss) Recognized in OCI on Derivative	$ (4,577)	$ 517	$ (5,301)	$ 1,030
Gain (Loss) Reclassified from Accumulated OCI into Income	1	(127)	(15)	(274)
Interest Rate Products
Derivative [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(4,577)	517	(5,301)	1,030
Settled Interest Rate Swaps
Derivative [Line Items]
Gain (Loss) Recognized in OCI on Derivative	0	0	0	0
Interest Expense
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income	(1)	127	15	274
Interest Expense | Interest Rate Products
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income	(43)	85	(69)	190
Interest Expense | Settled Interest Rate Swaps
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income	$ 42	$ 42	$ 84	$ 84