Loans Receivable, Part IV (Details) - USD ($) | 6 Months Ended | 12 Months Ended | |
Jun. 30, 2017 | Dec. 31, 2015 | Dec. 31, 2016 |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | $ 1,225,762,000 | | $ 1,177,884,000 |
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 | $ 4,175,000 | | 3,476,000 |
Total Impaired, with no Reserve, Recorded Investment | 10,562,000 | | 12,586,000 |
Total Impaired, Recorded Investment | 14,737,000 | | 16,062,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 4,584,000 | | 3,885,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 12,423,000 | | 14,929,000 |
Total Impaired, Unpaid Principal Balance, Total | 17,007,000 | | 18,814,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 1,174,000 | | 662,000 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 1,174,000 | | 662,000 |
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 | 1,861,000 | | 2,343,000 |
Total Impaired, Cumulative Charge-offs | 2,270,000 | | 2,752,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | |
Total Impaired with Reserve, Average Recorded Investment | 4,214,000 | $ 3,558,000 | |
Total Impaired with no Reserve, Average Recorded Investment | 10,748,000 | 12,901,000 | |
Total Impaired, Average Recorded Investment, Total | 14,962,000 | 16,459,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total Impaired with Reserve, Interest Paid YTD | 76,000 | 118,000 | |
Total Impaired with no Reserve, Interest Paid YTD | 248,000 | 655,000 | |
Total Impaired, Interest Paid YTD | 324,000 | 773,000 | |
Charge-offs recorded to reduce the unpaid principal balance | 1,900,000 | | |
Total impaired loans including troubled debt restructurings | 8,211,000 | | 10,137,000 |
Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 12,721,000 | | 15,458,000 |
Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 14,714,000 | | 20,129,000 |
Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 1,198,327,000 | | 1,142,297,000 |
Residential Real Estate [Member] | One- to four-family [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 412,139,000 | | 392,817,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 3,384,000 | | 3,007,000 |
Total Impaired, with no Reserve, Recorded Investment | 6,640,000 | | 7,913,000 |
Total Impaired, Recorded Investment | 10,024,000 | | 10,920,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 3,384,000 | | 3,007,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 7,612,000 | | 9,245,000 |
Total Impaired, Unpaid Principal Balance, Total | 10,996,000 | | 12,252,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 986,000 | | 499,000 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 986,000 | | 499,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 972,000 | | 1,332,000 |
Total Impaired, Cumulative Charge-offs | 972,000 | | 1,332,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | |
Total Impaired with Reserve, Average Recorded Investment | 3,410,000 | 3,063,000 | |
Total Impaired with no Reserve, Average Recorded Investment | 6,778,000 | 8,150,000 | |
Total Impaired, Average Recorded Investment, Total | 10,188,000 | 11,213,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total Impaired with Reserve, Interest Paid YTD | 65,000 | 88,000 | |
Total Impaired with no Reserve, Interest Paid YTD | 144,000 | 401,000 | |
Total Impaired, Interest Paid YTD | 209,000 | 489,000 | |
Total impaired loans including troubled debt restructurings | 4,515,000 | | 5,695,000 |
Residential Real Estate [Member] | One- to four-family [Member] | Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 9,647,000 | | 12,845,000 |
Residential Real Estate [Member] | One- to four-family [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 9,702,000 | | 10,509,000 |
Residential Real Estate [Member] | One- to four-family [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 392,790,000 | | 369,463,000 |
Residential Real Estate [Member] | Multi Family [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 574,468,000 | | 558,592,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 373,000 | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 3,313,000 | | 3,941,000 |
Total Impaired, Recorded Investment | 3,686,000 | | 3,941,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 373,000 | | 0 |
Total Impaired with no Reserve, Unpaid Principal Balance | 4,188,000 | | 4,952,000 |
Total Impaired, Unpaid Principal Balance, Total | 4,561,000 | | 4,952,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 45,000 | | 0 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 45,000 | | 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 | 875,000 | | 1,011,000 |
Total Impaired, Cumulative Charge-offs | 875,000 | | 1,011,000 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | |
Total Impaired with Reserve, Average Recorded Investment | 374,000 | 0 | |
Total Impaired with no Reserve, Average Recorded Investment | 3,344,000 | 4,005,000 | |
Total Impaired, Average Recorded Investment, Total | 3,718,000 | 4,005,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total Impaired with Reserve, Interest Paid YTD | 0 | 0 | |
Total Impaired with no Reserve, Interest Paid YTD | 95,000 | 230,000 | |
Total Impaired, Interest Paid YTD | 95,000 | 230,000 | |
Total impaired loans including troubled debt restructurings | 3,314,000 | | 3,941,000 |
Residential Real Estate [Member] | Multi Family [Member] | Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 1,198,000 | | 1,427,000 |
Residential Real Estate [Member] | Multi Family [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 2,989,000 | | 3,975,000 |
Residential Real Estate [Member] | Multi Family [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 570,281,000 | | 553,190,000 |
Residential Real Estate [Member] | Home Equity [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 21,046,000 | | 21,778,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 163,000 | | 188,000 |
Total Impaired, with no Reserve, Recorded Investment | 110,000 | | 254,000 |
Total Impaired, Recorded Investment | 273,000 | | 442,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 163,000 | | 188,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 110,000 | | 254,000 |
Total Impaired, Unpaid Principal Balance, Total | 273,000 | | 442,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 85,000 | | 79,000 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 85,000 | | 79,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | |
Total Impaired with Reserve, Average Recorded Investment | 167,000 | 198,000 | |
Total Impaired with no Reserve, Average Recorded Investment | 114,000 | 258,000 | |
Total Impaired, Average Recorded Investment, Total | 281,000 | 456,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total Impaired with Reserve, Interest Paid YTD | 6,000 | 15,000 | |
Total Impaired with no Reserve, Interest Paid YTD | 2,000 | 9,000 | |
Total Impaired, Interest Paid YTD | 8,000 | 24,000 | |
Total impaired loans including troubled debt restructurings | | | 146,000 |
Residential Real Estate [Member] | Home Equity [Member] | Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 242,000 | | 428,000 |
Residential Real Estate [Member] | Home Equity [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 53,000 | | 149,000 |
Residential Real Estate [Member] | Home Equity [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 20,751,000 | | 21,201,000 |
Construction and Land [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 14,906,000 | | 18,179,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | 0 |
Total Impaired, with no Reserve, Recorded Investment | 37,000 | | 0 |
Total Impaired, Recorded Investment | 37,000 | | 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 | 51,000 | | 0 |
Total Impaired, Unpaid Principal Balance, Total | 51,000 | | 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 | 14,000 | | 0 |
Total Impaired, Cumulative Charge-offs | 14,000 | | 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 | 49,000 | 0 | |
Total Impaired, Average Recorded Investment, Total | 49,000 | 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 Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 37,000 | | 0 |
Construction and Land [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 0 | | 436,000 |
Construction and Land [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 14,869,000 | | 17,743,000 |
Construction and Land [Member] | Home Equity [Member] | | | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total impaired loans including troubled debt restructurings | 48,000 | | |
Commercial Real Estate [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 176,934,000 | | 159,401,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 255,000 | | 280,000 |
Total Impaired, with no Reserve, Recorded Investment | 436,000 | | 438,000 |
Total Impaired, Recorded Investment | 691,000 | | 718,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 664,000 | | 689,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 436,000 | | 438,000 |
Total Impaired, Unpaid Principal Balance, Total | 1,100,000 | | 1,127,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 58,000 | | 83,000 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 58,000 | | 83,000 |
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 | 263,000 | 295,000 | |
Total Impaired with no Reserve, Average Recorded Investment | 437,000 | 442,000 | |
Total Impaired, Average Recorded Investment, Total | 700,000 | 737,000 | |
Impaired Loans Receivable, Interest Paid YTD [Abstract] | | | |
Total Impaired with Reserve, Interest Paid YTD | 5,000 | 15,000 | |
Total Impaired with no Reserve, Interest Paid YTD | 7,000 | 13,000 | |
Total Impaired, Interest Paid YTD | 12,000 | 28,000 | |
Total impaired loans including troubled debt restructurings | 334,000 | | 355,000 |
Commercial Real Estate [Member] | Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 691,000 | | 717,000 |
Commercial Real Estate [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 598,000 | | 1,389,000 |
Commercial Real Estate [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 175,645,000 | | 157,295,000 |
Consumer [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 291,000 | | 319,000 |
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 Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 0 | | 0 |
Consumer [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 0 | | 0 |
Consumer [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 291,000 | | 319,000 |
Commercial Loans [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 25,978,000 | | 26,798,000 |
Impaired Loans Receivable, Recorded Investment [Abstract] | | | |
Total Impaired, with Reserve, Recorded Investment | 0 | | 1,000 |
Total Impaired, with no Reserve, Recorded Investment | 26,000 | | 40,000 |
Total Impaired, Recorded Investment | 26,000 | | 41,000 |
Impaired Loans Receivable, Unpaid Principal Balance [Abstract] | | | |
Total Impaired with Reserve, Unpaid Principal Balance | 0 | | 1,000 |
Total Impaired with no Reserve, Unpaid Principal Balance | 26,000 | | 40,000 |
Total Impaired, Unpaid Principal Balance, Total | 26,000 | | 41,000 |
Impaired Loans Receivable, Reserve [Abstract] | | | |
Total Impaired with Reserve, Reserve | 0 | | 1,000 |
Total Impaired with no Reserve, Reserve | 0 | | 0 |
Impaired Loans, Reserve | 0 | | 1,000 |
Impaired Loans Receivable, Cumulative Charge Offs [Abstract] | | | |
Total Impaired with Reserve, Cumulative Charge-offs | 0 | | 0 |
Total Impaired with no Reserve, Cumulative Charge-offs | 0 | | 0 |
Total Impaired, Cumulative Charge-offs | 0 | | 0 |
Impaired Loans Receivable, Average Recorded Investment [Abstract] | | | |
Total Impaired with Reserve, Average Recorded Investment | 0 | 2,000 | |
Total Impaired with no Reserve, Average Recorded Investment | 26,000 | 46,000 | |
Total Impaired, Average Recorded Investment, Total | 26,000 | 48,000 | |
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 | 2,000 | |
Total Impaired, Interest Paid YTD | 0 | $ 2,000 | |
Commercial Loans [Member] | Substandard [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 906,000 | | 41,000 |
Commercial Loans [Member] | Watch [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | 1,372,000 | | 3,671,000 |
Commercial Loans [Member] | Pass [Member] | | | |
Loans Receivable, Recorded Investment [Line Items] | | | |
At December 31, 2016 | $ 23,700,000 | | $ 23,086,000 |