Stock-Based Compensation - Employee Stock Purchase Plan (Details) - shares	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016
Employee Stock Purchase Plan
Stock-based compensation
Total shares authorized		600,000
Shares available for future purchases		584,039
Employee Stock Purchase Plan
Stock-based compensation
Discount from the closing price on the exercise date (as a percent)		5.00%
Holding period for common stock purchased by plan participants		2 years
Shares issued to employee participants	15,961