Reporting For Segments (Summary of Net Sales by Geographic Region) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total net sales	$ 245,857	$ 246,291	$ 261,978	$ 264,240	$ 266,492	$ 267,739	$ 273,544	$ 274,448	$ 1,018,366	$ 1,082,223	$ 996,382
United States [Member]
Segment Reporting Information [Line Items]
Total net sales									359,267	379,912	356,483
Germany [Member]
Segment Reporting Information [Line Items]
Total net sales									149,270	148,706	122,808
Other International [Member]
Segment Reporting Information [Line Items]
Total net sales									$ 509,829	$ 553,605	$ 517,091