Shareholders' Equity - Additional Information (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Common Stock
Treasury Stock, Value, Acquired, Cost Method	$ 9,440
Treasury Stock, Shares, Acquired	342,100	0	0
Common stock repurchased, shares	342,100	0
Shares available for future purchases	$ 8,114