Loans Receivable, Part IV (Details) - USD ($) | 3 Months Ended | 6 Months Ended | |
Mar. 31, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2019 |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | $ 1,409,378,000 | | | $ 1,388,031,000 |
Loans requiring an officers' loans committee review and approval, minimum | 500,000 | | | |
Minimum amount of potential loan exposure to be reviewed by credit management personnel | $ 1,000,000 | | | |
Maximum period of time loan is reviewed if renewed | 1 year | | | |
Period of time sales of real estate owned fair value is based | 2 years | | | |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | $ 217,000 | | | 224,000 |
Total Impaired, with no Reserve, Recorded Investment | 9,602,000 | | | 9,833,000 |
Total Impaired, Recorded Investment | 9,819,000 | | | 10,057,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 626,000 | | | 633,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 11,443,000 | | | 11,680,000 |
Total Impaired, Unpaid Principal Balance, Total | 12,069,000 | | | 12,313,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 31,000 | | | 39,000 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 31,000 | | | 39,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 409,000 | | | 409,000 |
Total Impaired with no Reserve, Cumulative Charge-offs | 1,841,000 | | | 1,847,000 |
Total Impaired, Cumulative Charge-offs | 2,250,000 | | | 2,256,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | $ 221,000 | $ 3,270,000 | |
Total Impaired with no Reserve, Average Recorded Investment | | 9,658,000 | 9,139,000 | |
Total Impaired, Average Recorded Investment, Total | | 9,879,000 | 12,409,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 14,000 | 44,000 | |
Total Impaired with no Reserve, Interest Paid YTD | | 123,000 | 139,000 | |
Total Impaired, Interest Paid YTD | | 137,000 | 183,000 | |
Charge-offs recorded to reduce the unpaid principal balance | 1,800,000 | | | |
Total impaired loans including troubled debt restructurings | 3,929,000 | | | 4,018,000 |
Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 10,750,000 | | | 11,013,000 |
Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 7,301,000 | | | 8,237,000 |
Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 1,391,327,000 | | | 1,368,781,000 |
Residential Real Estate [Member] | One-to-Four Family [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 479,259,000 | | | 480,280,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 215,000 | | | 217,000 |
Total Impaired, with no Reserve, Recorded Investment | 8,224,000 | | | 8,508,000 |
Total Impaired, Recorded Investment | 8,439,000 | | | 8,725,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 215,000 | | | 217,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 9,242,000 | | | 9,531,000 |
Total Impaired, Unpaid Principal Balance, Total | 9,457,000 | | | 9,748,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 29,000 | | | 32,000 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 29,000 | | | 32,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 1,018,000 | | | 1,023,000 |
Total Impaired, Cumulative Charge-offs | 1,018,000 | | | 1,023,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 216,000 | 354,000 | |
Total Impaired with no Reserve, Average Recorded Investment | | 8,265,000 | 7,652,000 | |
Total Impaired, Average Recorded Investment, Total | | 8,481,000 | 8,006,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 4,000 | 6,000 | |
Total Impaired with no Reserve, Interest Paid YTD | | 98,000 | 114,000 | |
Total Impaired, Interest Paid YTD | | 102,000 | 120,000 | |
Total impaired loans including troubled debt restructurings | 3,359,000 | | | 3,425,000 |
Residential Real Estate [Member] | One-to-Four Family [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 8,438,000 | | | 8,725,000 |
Residential Real Estate [Member] | One-to-Four Family [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 5,205,000 | | | 5,975,000 |
Residential Real Estate [Member] | One-to-Four Family [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 465,616,000 | | | 465,580,000 |
Residential Real Estate [Member] | Multi Family [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 588,555,000 | | | 584,859,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 647,000 | | | 667,000 |
Total Impaired, Recorded Investment | 647,000 | | | 667,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 1,470,000 | | | 1,491,000 |
Total Impaired, Unpaid Principal Balance, Total | 1,470,000 | | | 1,491,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 0 | | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 0 | | | 0 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 823,000 | | | 824,000 |
Total Impaired, Cumulative Charge-offs | 823,000 | | | 824,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 0 | 349,000 | |
Total Impaired with no Reserve, Average Recorded Investment | | 656,000 | 945,000 | |
Total Impaired, Average Recorded Investment, Total | | 656,000 | 1,294,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 0 | 10,000 | |
Total Impaired with no Reserve, Interest Paid YTD | | 17,000 | 20,000 | |
Total Impaired, Interest Paid YTD | | 17,000 | 30,000 | |
Total impaired loans including troubled debt restructurings | 291,000 | | | 308,000 |
Residential Real Estate [Member] | Multi Family [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 647,000 | | | 668,000 |
Residential Real Estate [Member] | Multi Family [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 0 |
Residential Real Estate [Member] | Multi Family [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 587,908,000 | | | 584,191,000 |
Residential Real Estate [Member] | Home Equity [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 17,649,000 | | | 18,071,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 387,000 | | | 84,000 |
Total Impaired, Recorded Investment | 387,000 | | | 84,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 387,000 | | | 84,000 |
Total Impaired, Unpaid Principal Balance, Total | 387,000 | | | 84,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 0 | | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 0 | | | 0 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 0 | 86,000 | |
Total Impaired with no Reserve, Average Recorded Investment | | 388,000 | 138,000 | |
Total Impaired, Average Recorded Investment, Total | | 388,000 | 224,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 0 | 2,000 | |
Total Impaired with no Reserve, Interest Paid YTD | | 4,000 | 1,000 | |
Total Impaired, Interest Paid YTD | | 4,000 | 3,000 | |
Residential Real Estate [Member] | Home Equity [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 576,000 | | | 285,000 |
Residential Real Estate [Member] | Home Equity [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 3,000 |
Residential Real Estate [Member] | Home Equity [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 17,073,000 | | | 17,783,000 |
Construction and Land [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 44,655,000 | | | 37,033,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, Recorded Investment | 0 | | | 0 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired, Unpaid Principal Balance, Total | 0 | | | 0 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 0 | | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 0 | | | 0 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 0 | 0 | |
Total Impaired with no Reserve, Average Recorded Investment | | 0 | 0 | |
Total Impaired, Average Recorded Investment, Total | | 0 | 0 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired with no Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired, Interest Paid YTD | | 0 | 0 | |
Construction and Land [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 0 |
Construction and Land [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 0 |
Construction and Land [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 44,655,000 | | | 37,033,000 |
Commercial Real Estate [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 246,370,000 | | | 236,703,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 2,000 | | | 7,000 |
Total Impaired, with no Reserve, Recorded Investment | 344,000 | | | 574,000 |
Total Impaired, Recorded Investment | 346,000 | | | 581,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 411,000 | | | 416,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 344,000 | | | 574,000 |
Total Impaired, Unpaid Principal Balance, Total | 755,000 | | | 990,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 2,000 | | | 7,000 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 2,000 | | | 7,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 409,000 | | | 409,000 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired, Cumulative Charge-offs | 409,000 | | | 409,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 5,000 | 2,481,000 | |
Total Impaired with no Reserve, Average Recorded Investment | | 349,000 | 388,000 | |
Total Impaired, Average Recorded Investment, Total | | 354,000 | 2,869,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 10,000 | 26,000 | |
Total Impaired with no Reserve, Interest Paid YTD | | 4,000 | 4,000 | |
Total Impaired, Interest Paid YTD | | 14,000 | 30,000 | |
Total impaired loans including troubled debt restructurings | 279,000 | | | 285,000 |
Commercial Real Estate [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 346,000 | | | 581,000 |
Commercial Real Estate [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 1,397,000 | | | 1,412,000 |
Commercial Real Estate [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 244,627,000 | | | 234,710,000 |
Consumer [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 890,000 | | | 832,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, Recorded Investment | 0 | | | 0 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired, Unpaid Principal Balance, Total | 0 | | | 0 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 0 | | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 0 | | | 0 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 0 | 0 | |
Total Impaired with no Reserve, Average Recorded Investment | | 0 | 0 | |
Total Impaired, Average Recorded Investment, Total | | 0 | 0 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired with no Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired, Interest Paid YTD | | 0 | 0 | |
Consumer [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 0 |
Consumer [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 0 | | | 0 |
Consumer [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 890,000 | | | 832,000 |
Commercial Loans [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 32,000,000 | | | 30,253,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 0 | | | 0 |
Total Impaired, Recorded Investment | 0 | | | 0 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 0 | | | 0 |
Total Impaired, Unpaid Principal Balance, Total | 0 | | | 0 |
Impaired Loans Receivable, Reserve [Abstract] | | | | |
Total Impaired with Reserve, Reserve | 0 | | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | | 0 |
Impaired Loans, Reserve | 0 | | | 0 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | | |
Total Impaired with Reserve, Average Recorded Investment | | 0 | 0 | |
Total Impaired with no Reserve, Average Recorded Investment | | 0 | 16,000 | |
Total Impaired, Average Recorded Investment, Total | | 0 | 16,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | | |
Total Impaired with Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired with no Reserve, Interest Paid YTD | | 0 | 0 | |
Total Impaired, Interest Paid YTD | | $ 0 | $ 0 | |
Commercial Loans [Member] | Substandard [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 743,000 | | | 754,000 |
Commercial Loans [Member] | Watch [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | 699,000 | | | 847,000 |
Commercial Loans [Member] | Pass [Member] | | | | |
Loans and Leases Receivable [Abstract] | | | | |
At December 31, 2016 | $ 30,558,000 | | | $ 28,652,000 |