Stock-Based Compensation - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Jun. 30, 2017	Sep. 30, 2017
Employee Stock Purchase Plan
Offering period		6 months
Contribution maximum percentage of pay		10.00%
Contribution maximum amount per year		$ 10
Contribution maximum amount per offering period		$ 5
Discount applied to closing price, percentage		10.00%
Shares purchased under Employee Stock Purchase Plan	29,668
Price per share (in dollars per share)	$ 33.43
Holding period (in days)	90 days