Debt (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Debt
Interest expense	$ 1,900	$ 1,300	$ 3,300	$ 2,400
Scheduled principal payments
2015	1,109		1,109
2016	9,757		9,757
2017	40,597		40,597
2018	192,265		192,265
2019	20,081		20,081
Thereafter	22,173		22,173
Total principal	$ 285,982		$ 285,982		$ 216,105