Derivatives (Terminated Derivatives) (Details)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) instrument	Sep. 30, 2017 USD ($) instrument	Dec. 31, 2016 USD ($) instrument	Oct. 31, 2015 USD ($) instrument	May 31, 2014 USD ($) instrument	Apr. 30, 2013 USD ($) instrument
Derivative [Line Items]
Fair Value Deferred In Other Comprehensive Income	$ (11,738,000)
Forward Swap
Derivative [Line Items]
Number of interest rate derivatives terminated | instrument		2	2	2	4	3	4
Aggregate Notional Amount	$ 200,000,000	$ 250,000,000	$ 250,000,000	$ 180,000,000	$ 300,000,000	$ 225,000,000	$ 240,000,000
Liability Fair Value When Terminated			7,690,000		13,369,000	6,312,000	3,156,000
Asset Fair Value When Terminated		(4,080,000)		(13,352,000)
Fair Value Deferred In Other Comprehensive Income		$ (4,080,000)	$ 7,688,000	$ (13,345,000)	$ 13,369,000	$ 6,312,000	$ 3,141,000