Loans (Details 2) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Ending allowance balance attributable to loans:
Individually evaluated for impairment	$ 580	$ 595
Collectively evaluated for impairment	27,584,000	27,736,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	28,164,000	28,331,000
Loans:
Loans individually evaluated for impairment	42,269,000	45,940,000
Loans collectively evaluated for impairment	2,513,897,000	2,500,222,000
Loans acquired with deteriorated credit quality	2,272,000	2,331,000
Total ending loans balance	2,558,438,000	2,548,493,000
One to Four Family Residential Real Estate [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	177,000	175,000
Collectively evaluated for impairment	2,634,000	2,706,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	2,811,000	2,881,000
Loans:
Loans individually evaluated for impairment	6,640,000	6,774,000
Loans collectively evaluated for impairment	314,510,000	315,385,000
Loans acquired with deteriorated credit quality	1,007,000	1,012,000
Total ending loans balance	322,157,000	323,171,000
Multi Family Residential Real Estate [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	2,000	3,000
Collectively evaluated for impairment	3,066,000	3,098,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	3,068,000	3,101,000
Loans:
Loans individually evaluated for impairment	1,333,000	1,347,000
Loans collectively evaluated for impairment	278,011,000	277,105,000
Loans acquired with deteriorated credit quality	294,000	296,000
Total ending loans balance	279,638,000	278,748,000
Commercial Real Estate [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	98,000	95,000
Collectively evaluated for impairment	11,903,000	11,946,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	12,001,000	12,041,000
Loans:
Loans individually evaluated for impairment	23,297,000	26,334,000
Loans collectively evaluated for impairment	1,095,031,000	1,102,355,000
Loans acquired with deteriorated credit quality	808,000	846,000
Total ending loans balance	1,119,136,000	1,129,535,000
Construction Loans [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	731,000	682,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	731,000	682,000
Loans:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	166,137,000	142,096,000
Loans acquired with deteriorated credit quality	0	0
Total ending loans balance	166,137,000	142,096,000
Commercial Loan [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	67,000	79,000
Collectively evaluated for impairment	7,209,000	7,202,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	7,276,000	7,281,000
Loans:
Loans individually evaluated for impairment	10,052,000	10,477,000
Loans collectively evaluated for impairment	501,403,000	500,730,000
Loans acquired with deteriorated credit quality	163,000	177,000
Total ending loans balance	511,618,000	511,384,000
Home Equity and Home Improvement [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment	236,000	242,000
Collectively evaluated for impairment	1,692,000	1,784,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	1,928,000	2,026,000
Loans:
Loans individually evaluated for impairment	914,000	963,000
Loans collectively evaluated for impairment	124,443,000	128,065,000
Loans acquired with deteriorated credit quality	0	0
Total ending loans balance	125,357,000	129,028,000
Consumer Finance [Member]
Ending allowance balance attributable to loans:
Individually evaluated for impairment		1,000
Collectively evaluated for impairment	349,000	318,000
Acquired with deteriorated credit quality	0	0
Total ending allowance balance	349,000	319,000
Loans:
Loans individually evaluated for impairment	33,000	45,000
Loans collectively evaluated for impairment	34,362,000	34,486,000
Loans acquired with deteriorated credit quality	0	0
Total ending loans balance	$ 34,395,000	$ 34,531,000