Stock Repurchase Program (Details Textual) - USD ($)			3 Months Ended		12 Months Ended
	Dec. 18, 2018	Jan. 23, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	May 22, 2018
Equity Class Of Treasury Stock [Line Items]
Common stock, shares outstanding			4,352,394		4,349,624
Stock repurchase program, shares repurchased				10,488
Stock Repurchase Program on January 23, 2018
Equity Class Of Treasury Stock [Line Items]
Shares authorized to be repurchased						300,000
Percentage of shares authorized to be repurchased to common stock outstanding		2.30%
Common stock, shares outstanding		4,420,136
Stock repurchase program, remaining authorized amount			$ 7,100,000
Stock repurchase program expiration date			Dec. 31, 2018
Stock repurchase program, shares repurchased					80,944
Increase in number of shares authorized to be repurchased						200,000
Stock Repurchase Program on January 23, 2018 | Maximum
Equity Class Of Treasury Stock [Line Items]
Shares authorized to be repurchased		100,000
Stock Repurchase Program on December 18,2018
Equity Class Of Treasury Stock [Line Items]
Percentage of shares authorized to be repurchased to common stock outstanding	6.90%
Common stock, shares outstanding	4,349,624
Stock repurchase program expiration date			Dec. 31, 2019
Stock repurchase program, shares repurchased			0
Stock Repurchase Program on December 18,2018 | Maximum
Equity Class Of Treasury Stock [Line Items]
Shares authorized to be repurchased	300,000