Leases (Operating Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Long-term fixed lease expense	$ 22,855	$ 33,577	$ 33,642
Long-term variable lease expense	385	406	749
Short-term lease expense	10,482	17,670	14,367
Total operating lease expense	$ 33,722	$ 51,653	$ 48,758