Stockholders' Equity - Common Stock Repurchase (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Apr. 25, 2017
Common Stock Repurchase
Shares repurchased (in dollars)	$ 2,866
Treasury Stock
Common Stock Repurchase
Shares repurchased (in shares)	80,000
Average price per share (in dollars per share)	$ 35.82
Shares repurchased (in dollars)	$ 2,866
Common Stock
Common Stock Repurchase
Number of shares authorized to be repurchased		$ 5,000
Common stock available for repurchase	$ 1,175