Revenue From Contracts With Customers (Disaggregation of Revenue, By Timing) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Timing of Revenue Recognition
Total	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
Goods and services transferred at a point in time
Timing of Revenue Recognition
Total	308,474	310,324	824,069	944,454
Goods and services transferred over time
Timing of Revenue Recognition
Total	$ 9,967	$ 18,814	$ 40,025	$ 63,500