Shareholders' Equity - Narrative (Details)	1 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2017 vote shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)	Feb. 25, 2016 USD ($)
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)		8,520,328	7,633,070
Common stock, shares issued (in shares)		8,520,328	7,633,070
Common equity issued | $	$ 5,000,000
Stock repurchased during period, value | $			$ 625,000	$ 6,275,000
Common Stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)		8,520,328	7,633,070
Common stock, shares issued (in shares)		8,520,328	7,633,070
Stock repurchased during period, shares (in shares)			88,650
Stock repurchased during period, value | $			$ 625,000
Common stock voting rights, number of votes per share | vote		1
Stock Repurchase Program, February 2016 | Common Stock
Class of Stock [Line Items]
Authorized amount of stock repurchase program (in shares) | $					$ 2,100,000.0
Stock repurchased during period, shares (in shares)		0	88,650
Stock repurchased during period, value | $			$ 625,000
Private Placement
Class of Stock [Line Items]
Common equity issued (in shares)	800,000
Price per share (in dollars per share) | $ / shares	$ 6.25