Leased Property (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Leased Property
Right of use assets - operating	$ 55,582		$ 55,582
Right of use asset - finance	40,010		40,010
Capitalized costs of lessor assets	43,249		43,249		$ 98,877
Less: accumulated depreciation	(8,826)		(8,826)		(11,812)
Leased property, net	130,015		130,015		$ 87,065
Depreciation	2,200	$ 1,900	6,800	$ 5,200
Right of use asset depreciation	$ 1,600		$ 4,900