Securities, Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	3 Months Ended		6 Months Ended			12 Months Ended
	Dec. 31, 2017 USD ($) Security	Dec. 31, 2016 USD ($)	Jun. 30, 2018	Dec. 31, 2017 USD ($) Security	Dec. 31, 2016 USD ($)	Jun. 30, 2019	Jun. 30, 2017 USD ($) Security
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 12,287			$ 12,287			$ 8,412
Less than 12 months, unrealized losses	$ 190			$ 190			$ 92
Less than 12 months, number of securities | Security	10			10			7
More than 12 months, fair value	$ 757			$ 757			$ 0
More than 12 months, unrealized losses	$ 3			$ 3			$ 0
More than 12 months, number of securities | Security	2			2			0
Total, fair value	$ 13,044			$ 13,044			$ 8,412
Total, unrealized losses	$ 193			$ 193			$ 92
Total, number of securities | Security	12			12			7
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 69,062			$ 69,062			$ 42,072
Less than 12 months, unrealized losses	$ 597			$ 597			$ 346
Less than 12 months, number of securities | Security	144			144			84
More than 12 months, fair value	$ 7,285			$ 7,285			$ 588
More than 12 months, unrealized losses	$ 105			$ 105			$ 20
More than 12 months, number of securities | Security	38			38			7
Total, fair value	$ 76,347			$ 76,347			$ 42,660
Total, unrealized losses	$ 702			$ 702			$ 366
Total, number of securities | Security	182			182			91
Income Tax Disclosure [Line Items]
Federal corporate tax rate				35.00%
Total Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 81,349			$ 81,349			$ 50,484
Less than 12 months, unrealized losses	$ 787			$ 787			$ 438
Less than 12 months, number of securities | Security	154			154			91
More than 12 months, fair value	$ 8,042			$ 8,042			$ 588
More than 12 months, unrealized losses	$ 108			$ 108			$ 20
More than 12 months, number of securities | Security	40			40			7
Total, fair value	$ 89,391			$ 89,391			$ 51,072
Total, unrealized losses	$ 895			$ 895			$ 458
Total, number of securities | Security	194			194			98
Proceeds from sale of available-for-sale securities, debt	$ 0	$ 0		$ 0	$ 0
Gross realized gains (losses) on sale of available-for-sale securities	0	0		0	0
Other-than-temporary impairment losses	0	$ 0		0	$ 0
Forecast [Member]
Income Tax Disclosure [Line Items]
Federal corporate tax rate			21.00%			21.00%
U.S. Government Sponsored Enterprises [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	985			985
Less than 12 months, unrealized losses	$ 12			$ 12
Less than 12 months, number of securities | Security	1			1
More than 12 months, fair value	$ 0			$ 0
More than 12 months, unrealized losses	$ 0			$ 0
More than 12 months, number of securities | Security	0			0
Total, fair value	$ 985			$ 985
Total, unrealized losses	$ 12			$ 12
Total, number of securities | Security	1			1
State and Political Subdivisions [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 2,122			$ 2,122
Less than 12 months, unrealized losses	$ 4			$ 4
Less than 12 months, number of securities | Security	3			3
More than 12 months, fair value	$ 0			$ 0
More than 12 months, unrealized losses	$ 0			$ 0
More than 12 months, number of securities | Security	0			0
Total, fair value	$ 2,122			$ 2,122
Total, unrealized losses	$ 4			$ 4
Total, number of securities | Security	3			3
Mortgage-backed Securities-Residential [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 1,051			$ 1,051			$ 1,164
Less than 12 months, unrealized losses	$ 43			$ 43			$ 27
Less than 12 months, number of securities | Security	1			1			1
More than 12 months, fair value	$ 0			$ 0			$ 0
More than 12 months, unrealized losses	$ 0			$ 0			$ 0
More than 12 months, number of securities | Security	0			0			0
Total, fair value	$ 1,051			$ 1,051			$ 1,164
Total, unrealized losses	$ 43			$ 43			$ 27
Total, number of securities | Security	1			1			1
Mortgage-backed Securities-Multi-family [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 8,129			$ 8,129			$ 6,488
Less than 12 months, unrealized losses	$ 131			$ 131			$ 62
Less than 12 months, number of securities | Security	5			5			4
More than 12 months, fair value	$ 0			$ 0			$ 0
More than 12 months, unrealized losses	$ 0			$ 0			$ 0
More than 12 months, number of securities | Security	0			0			0
Total, fair value	$ 8,129			$ 8,129			$ 6,488
Total, unrealized losses	$ 131			$ 131			$ 62
Total, number of securities | Security	5			5			4
Corporate Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 0			$ 0			$ 760
Less than 12 months, unrealized losses	$ 0			$ 0			$ 3
Less than 12 months, number of securities | Security	0			0			2
More than 12 months, fair value	$ 757			$ 757			$ 0
More than 12 months, unrealized losses	$ 3			$ 3			$ 0
More than 12 months, number of securities | Security	2			2			0
Total, fair value	$ 757			$ 757			$ 760
Total, unrealized losses	$ 3			$ 3			$ 3
Total, number of securities | Security	2			2			2
U.S. Government Sponsored Enterprises [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 5,181			$ 5,181			$ 5,947
Less than 12 months, unrealized losses	$ 64			$ 64			$ 53
Less than 12 months, number of securities | Security	1			1			2
More than 12 months, fair value	$ 1,969			$ 1,969			$ 0
More than 12 months, unrealized losses	$ 31			$ 31			$ 0
More than 12 months, number of securities | Security	1			1			0
Total, fair value	$ 7,150			$ 7,150			$ 5,947
Total, unrealized losses	$ 95			$ 95			$ 53
Total, number of securities | Security	2			2			2
State and Political Subdivisions [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	$ 18,840			$ 18,840			$ 8,976
Less than 12 months, unrealized losses	$ 142			$ 142			$ 76
Less than 12 months, number of securities | Security	116			116			64
More than 12 months, fair value	$ 3,892			$ 3,892			$ 514
More than 12 months, unrealized losses	$ 63			$ 63			$ 19
More than 12 months, number of securities | Security	35			35			6
Total, fair value	$ 22,732			$ 22,732			$ 9,490
Total, unrealized losses	$ 205			$ 205			$ 95
Total, number of securities | Security	151			151			70
Mortgage-backed Securities-Residential [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value							$ 1,864
Less than 12 months, unrealized losses							$ 2
Less than 12 months, number of securities | Security							1
More than 12 months, fair value							$ 0
More than 12 months, unrealized losses							$ 0
More than 12 months, number of securities | Security							0
Total, fair value							$ 1,864
Total, unrealized losses	$ 0			$ 0			$ 2
Total, number of securities | Security							1
Mortgage-backed Securities-Multi-family [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	44,450			44,450			$ 23,823
Less than 12 months, unrealized losses	$ 388			$ 388			$ 199
Less than 12 months, number of securities | Security	26			26			15
More than 12 months, fair value	$ 1,424			$ 1,424			$ 0
More than 12 months, unrealized losses	$ 11			$ 11			$ 0
More than 12 months, number of securities | Security	2			2			0
Total, fair value	$ 45,874			$ 45,874			$ 23,823
Total, unrealized losses	$ 399			$ 399			$ 199
Total, number of securities | Security	28			28			15
Corporate Debt Securities [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value							$ 995
Less than 12 months, unrealized losses							$ 5
Less than 12 months, number of securities | Security							1
More than 12 months, fair value							$ 0
More than 12 months, unrealized losses							$ 0
More than 12 months, number of securities | Security							0
Total, fair value							$ 995
Total, unrealized losses	$ 0			$ 0			$ 5
Total, number of securities | Security							1
Other Securities [Member]
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract]
Less than 12 months, fair value	591			591			$ 467
Less than 12 months, unrealized losses	$ 3			$ 3			$ 11
Less than 12 months, number of securities | Security	1			1			1
More than 12 months, fair value	$ 0			$ 0			$ 74
More than 12 months, unrealized losses	$ 0			$ 0			$ 1
More than 12 months, number of securities | Security	0			0			1
Total, fair value	$ 591			$ 591			$ 541
Total, unrealized losses	$ 3			$ 3			$ 12
Total, number of securities | Security	1			1			2