Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Employer contribution for defined contribution plans	$ 1,842	$ 1,784	$ 1,723
Required service period	10 years
Ultimate health care cost trend rate	6.00%	6.00%
Accumulated benefit obligation	$ 43,482	$ 39,049
Employees Younger Than Sixty-Five [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	6.00%
Employees Aged Sixty-Five Or Older [Member]
Defined Benefit Plan Disclosure [Line Items]
Ultimate health care cost trend rate	5.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage	50.00%
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage	50.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - benefit obligations	3.38%
Accumulated benefit obligation	$ 43,482	$ 39,049
Recognized net actuarial loss	$ 11,335
Key Executive SERP Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - benefit obligations	3.04%
Manager SERP Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - benefit obligations	3.30%
Director Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - benefit obligations	2.35%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate - benefit obligations	2.76%
Recognized net actuarial loss	$ 5,532