Lessor Leases Operating Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Operating Leased Assets [Line Items]
Rental income	$ 3,287	$ 2,790
Total property and equipment, net	52,039		$ 51,500
Accumulated depreciation and amortization	103,228		100,789
Depreciation	$ 4,000	3,500
Minimum
Operating Leased Assets [Line Items]
Term of Contract ( in years )	1 year
Maximum
Operating Leased Assets [Line Items]
Term of Contract ( in years )	7 years
Equipment
Operating Leased Assets [Line Items]
Depreciation		$ 100
Equipment
Operating Leased Assets [Line Items]
Total property and equipment, net	$ 2,500		2,600
Accumulated depreciation and amortization	1,300		$ 1,200
Depreciation	$ 100