Leased Assets and Liabilities (Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lease Cost
Operating lease expense	$ 48,503	$ 43,727	$ 41,676
Finance lease expense
Finance lease expense	3,372	2,697	2,295
Amortization of leased assets	700	527	465
Interest on lease liabilities	23,188	21,864	20,838
Sublease income	(1,948)	(1,735)	(736)
Total expense	$ 73,815	$ 67,080	$ 64,538