Derivatives (Terminated Derivatives) (Details) - Forward Swap	Mar. 31, 2020 USD ($) instrument	Sep. 30, 2019 instrument	Sep. 30, 2018 USD ($) instrument	Dec. 31, 2017 instrument	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2015 USD ($) instrument	May 31, 2014 USD ($) instrument
Derivative [Line Items]
Number of interest rate derivatives terminated | instrument	3	2	2	2			4	3
Aggregate Notional Amount	$ 200,000,000		$ 250,000,000		$ 250,000,000	$ 180,000,000	$ 300,000,000	$ 225,000,000
Liability Fair Value When Terminated	13,141,000				7,690,000		13,369,000	6,312,000
Asset Fair Value When Terminated			(4,080,000)			(13,352,000)
Fair Value Deferred In Other Comprehensive Income	$ 13,141,000		$ (4,080,000)		$ 7,688,000	$ (13,345,000)	$ 13,369,000	$ 6,312,000