Leased Assets and Liabilities (Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lease Cost
Operating lease expense	$ 54,718	$ 48,503	$ 43,727
Finance lease expense
Finance lease expense	3,792	3,372	2,697
Amortization of leased assets	949	700	527
Interest on lease liabilities	21,413	23,188	21,864
Sublease income	(979)	(1,948)	(1,735)
Total expense	$ 79,893	$ 73,815	$ 67,080