Other Assets (Schedule of Other Long-term Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Assets Noncurrent [Abstract]
Operating leases	$ 15,772
Mineral rights	5,254	$ 5,735
Investment in company owned life insurance (COLI), net	4,157	3,104
Real estate development costs	3,776	2,649
Debt issuance costs	1,846	2,405
Interest rate swaps	1,601	1,510
Restricted cash	944	2,802
Other	1,940	3,076
Total other long-term assets	$ 35,290	$ 21,281