Incentive Plan - Summary of Stock Options Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Number of Options Granted
Outstanding, beginning of period (in shares)	323,770
Options granted (in shares)	320,532
Options forfeited (in shares)	(2,158)
Options exercised (in shares)	0	0
Outstanding, end of period (in shares)	642,144
Exercisable, end of period, number of options granted (in shares)	1,080
Vested or expected to vest, end of period, number of options granted (in shares)	642,144
Weighted Average Exercise Price
Outstanding, beginning of period (dollars per share)	$ 36.55
Options granted (dollars per share)	41.90
Options forfeited (dollars per share)	36.55
Options exercised (dollars per share)	0.00
Outstanding, end of period (dollars per share)	39.22
Exercisable, end of period (dollars per share)	36.55
Vested or expected to vest, end of period (dollars per share)	$ 39.22
Weighted Average Remaining Contractual Term
Outstanding, end of period	9 years 6 months 26 days
Exercisable, end of period	9 years 5 months 23 days
Vested or expected to vest, end of period	9 years 6 months 26 days
Aggregate Intrinsic Value
Outstanding, end of period	$ 0
Exercisable, end of period	0
Vested or expected to vest, end of period	$ 0