Business Segment Information (Reconciliation of Total Operating Profit) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Total operating profit from segments	$ 129,377	$ 136,874	$ 375,291	$ 397,179
Income from operations	111,337	120,637	321,877	344,334
Operating Segments
Segment Reporting Information [Line Items]
Total operating profit from segments	129,377	136,874	375,291	397,179
Corporate
Segment Reporting Information [Line Items]
Corporate overhead expenses	$ (18,040)	$ (16,237)	$ (53,414)	$ (52,845)