Credit Quality of Loans and the Allowance for Loan Losses (Schedule of Troubled Debt Restructurings) (Details) - One-to-four family residential [Member] $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) N	Sep. 30, 2016 USD ($) N	Sep. 30, 2017 USD ($) N	Sep. 30, 2016 USD ($) N
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Loans | N			2	8
Pre-modification Recorded Principal Balance			$ 134	$ 412
Post-modification Recorded Principal Balance			$ 134	$ 412