Revenue Recognition (Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Accounts receivable (including long-term, included in Other assets)	$ 1,121,834	$ 1,081,070
Contract assets, short-term (included in Other current assets)	7,283	9,830
Contract assets, long-term (included in Other assets)	9,964	942
Contract liabilities (Deferred revenue)	63,921	$ 71,048
Revenue recognized relating to the contract liability	$ 47,200