Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property and Equipment
Total property and equipment	$ 1,728,350	$ 1,727,721
Less accumulated depreciation	615,174	595,089
Total	1,113,176	1,132,632
Assets held for sale	12,600	8,100
Long-lived assets subject to impairment	49,600
Buildings and improvements
Property and Equipment
Total property and equipment	1,140,047	1,126,645
Land
Property and Equipment
Total property and equipment	455,847	456,334
Fixtures and equipment
Property and Equipment
Total property and equipment	44,969	44,479
Idle Plant Assets [Member]
Property and Equipment
Total property and equipment	30,500	30,500
Long-lived assets subject to impairment	30,500
Construction in process
Property and Equipment
Total property and equipment	24,451	37,636
Capitalized internal use software
Property and Equipment
Total property and equipment	$ 32,536	$ 32,127