Stockholders' Equity - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Aug. 28, 2017
Equity [Abstract]
Authorized increase to stock repurchase plan			$ 40,000,000
Common stock available for future share repurchases, amount	$ 35,000,000		$ 200,000
Total repurchase costs	$ 2,800,000
Number of shares repurchased (in shares)	123,291	0