Leased Property (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Less: accumulated depreciation	$ (7,799)		$ (7,799)		$ (4,544)
Leased property under capital lease, net	70,293		70,293		54,060
Leased property.
Leased property under capital lease	78,092		78,092		58,604
Less: accumulated depreciation	(7,799)		(7,799)		(4,544)
Leased property under capital lease, net	70,293		70,293		$ 54,060
Depreciation	$ 1,700	$ 500	$ 3,300	$ 700