Debt - Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt maturities
2019	$ 294,000
2020	150,000
2021	100,000
Thereafter	150,000
Total principal outstanding	694,000	$ 392,250
Unamortized deferred financing costs	(3,550)	(1,243)
Total debt	$ 690,450	$ 391,007