Stock-Based Compensation - Summary Of Changes In CSEs Outstanding (Details) - Common stock equivalents	9 Months Ended
	Sep. 30, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Base fee percentage (up to)	50.00%
Common Stock Equivalents (CSEs) [Roll Forward]
Outstanding at December 31, 2016 (in shares) | shares	107,338
Granted (in shares) | shares	4,382
Converted to common shares upon grant (in shares) | shares	(3,177)
Outstanding at September 30, 2017 (in shares) | shares	108,543
Per Share Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding at December 31, 2016 (in dollars per share) | $ / shares	$ 20.74
Granted (in dollars per share) | $ / shares	118.75
Converted to common shares upon grant (in dollars per share) | $ / shares	118.71
Outstanding at September 30, 2017 (in dollars per share) | $ / shares	$ 21.82