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Securities - Amortized Cost and Fair Value of Available-for-sale Securities (Q2) (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 160,547,000	$ 153,566,000	$ 131,046,000
Gross Unrealized Gains	179,000	165,000
Gross Unrealized Losses	(4,149,000)	(1,787,000)
Fair Value	156,577,182	151,944,567	129,421,914
U.S. Government-sponsored enterprises (GSEs) [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	29,137,000	26,207,000	$ 18,279,000
Gross Unrealized Gains	0	1,000
Gross Unrealized Losses	(1,009,000)	(432,000)
Fair Value	28,128,000	25,776,000
Municipal securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	15,896,000	9,122,000
Gross Unrealized Gains	8,000	28,000
Gross Unrealized Losses	(320,000)	(147,000)
Fair Value	15,584,000	9,003,000
Other debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	976,000	974,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(65,000)	(24,000)
Fair Value	911,000	950,000
Mortgage-backed securities (GSEs) [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	114,538,000	117,263,000
Gross Unrealized Gains	171,000	136,000
Gross Unrealized Losses	(2,755,000)	(1,184,000)
Fair Value	$ 111,954,000	$ 116,215,000

X

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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