Loans Receivable (Allowance for Loan Losses by Segment) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	$ 557,027	$ 500,375	$ 538,319	$ 487,114
Charge-offs	47,604	20,058	48,396	24,868
Recoveries	2,423	133	2,423	204
Provisions	19,500	18,000	39,000	36,000
Ending Balance	531,346	498,450	531,346	498,450
One-to-four family residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	402,310	331,736	393,341	319,849
Charge-offs	19,276	6,135	19,276	10,945
Recoveries	2,423	133	2,423	133
Provisions	(16,381)	792	(7,412)	17,489
Ending Balance	369,076	326,526	369,076	326,526
Non-owner occupied one-to-four family residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	26,893	28,696	25,893	28,231
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provisions	(243)	1,654	757	2,119
Ending Balance	26,650	30,350	26,650	30,350
Commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	32,255	40,799	33,204	37,135
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provisions	(3,121)	(2,346)	(4,070)	1,318
Ending Balance	29,134	38,453	29,134	38,453
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning Balance	95,569	99,144	85,881	101,899
Charge-offs	28,328	13,923	29,120	13,923
Recoveries	0	0	0	71
Provisions	39,245	17,900	49,725	15,074
Ending Balance	$ 106,486	$ 103,121	$ 106,486	$ 103,121