Property and Equipment, Net (Schedule of Property and Equipment, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property and Equipment [Line Items]
Property and equipment	$ 1,696,400	$ 1,613,500
Less accumulated depreciation and amortization	(896,900)	(865,700)
Property and equipment, net	799,479	747,808
Land [Member]
Property and Equipment [Line Items]
Property and equipment	4,600	4,600
Building and Leasehold Improvements [Member]
Property and Equipment [Line Items]
Property and equipment	33,000	30,300
Machinery and Equipment [Member]
Property and Equipment [Line Items]
Property and equipment	1,460,600	1,391,800
Office Furniture and Equipment [Member]
Property and Equipment [Line Items]
Property and equipment	172,100	166,700
Construction in Progress [Member]
Property and Equipment [Line Items]
Property and equipment	$ 26,100	$ 20,100