Acquisition (Details) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	May 31, 2018
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares				3,253,060
Assets	$ 1,632,387	$ 1,636,927		$ 1,636,927
Interest-bearing demand deposits	5,169	1,730		1,730
Liabilities	1,408,369	1,417,942		1,417,942
Deposits	1,347,857	1,300,919		1,300,919
Goodwill	59,221	$ 59,221		$ 59,221
Business Acquisition, Share Price | $ / shares		$ 0.1955		$ 0.1955
Columbus First Bancorp, Inc. [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Less common stock issued		$ 63,598	$ 63,598	$ 63,598
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Equity Interests		0
Less cash paid for the common stock			783	783
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Payments To Acquire Business, Gross		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		13,679	13,679	13,679
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Cash and Equivalents		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets		10,350	10,350	10,350
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets		0
Number of branches					1
Equity interest exchange ratio					2
Business combination, consideration transferred			64,381	64,381
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Federal Home Loan Bank Stock		1,207	1,207	1,207
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Federal Home Loan Bank Stock		0
Business Combination, Acquired Receivable, Fair Value		282,133	282,748	282,133
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Loans Receivable		(615)
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loan Receivables Held For Sale		1,819	1,819	1,819
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Loan Receivables Held For Sale		0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		102	102	102
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		2,177	2,089	2,177
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles		88
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Real Estate Owned		35	35	35
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Real Estate Owned		0
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets		352	0	352
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Tax Assets		352
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		1,364	2,022	1,364
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other Noncurrent Assets		(658)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		313,218	314,051	313,218
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Assumed Assets		(833)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Liabilities		244,430	245,036	244,430
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities		(606)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt		22,943	22,920	22,943
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Current Liabilities, Long-Term Debt		23
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Short-term Borrowings		10,000	10,000	10,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Current Liabilities, Short-Term Borrowings		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		0	200	0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Tax Liabilities		(200)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		502	491	502
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Noncurrent Liabilities, Other		11
Liabilities assumed		277,875	278,647	277,875
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Assumed Liabilities		(772)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		35,343	35,404	35,343
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Recognized Identifiable Assets Acquired And Liabilities Assumed, Net	$ 0	(61)
Goodwill		29,038	$ 28,977	$ 29,038
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill		$ 61