Stock-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units (RSU)	3 Months Ended
	Mar. 31, 2019 $ / shares shares
Restricted Stock Units
Balance at Beginning of Period (in units) | shares	3,377
Granted (in units) | shares	3,901
Balance at End of Period (in units) | shares	7,278
Weighted Average Grant Date Fair Value
Outstanding at Beginning of period (in dollars per unit) | $ / shares	$ 32.57
Granted (in dollars per unit) | $ / shares	31.71
Outstanding at End of period (in dollars per unit) | $ / shares	$ 32.11