Leased Assets and Liabilities (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flow Information
Operating cash outflows - operating leases	$ 44,252	$ 40,599	$ 39,192
Operating cash outflows - finance leases	700	527	465
Financing cash outflows - finance leases	3,096	2,564	2,185
Leased assets obtained in exchange for new lease obligations
Operating leases	87,160	36,260	33,788
Finance leases	$ 4,072	$ 5,715	$ 3,325