Goodwill and Other Intangible Assets (2018 Acquisitions) (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Line Items]
Cash, net of cash acquired	$ 24,971	$ 179,481	$ 6,684
Business combinations, contingent consideration liabilities, range of potential undiscounted earn-out liabilities, high	179,000
2018 Acquisitions [Member]
Business Combinations [Line Items]
Cash, net of cash acquired	5,100
Business combinations, contingent consideration, earn-out liabilities	1,500
Business combinations, contingent consideration liabilities, range of potential undiscounted earn-out liabilities, high	$ 4,000