Segment Information (Net Sales by Region or Origin and Long-Lived Assets by Region of Domicile) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 258,112	$ 274,574	$ 247,627	$ 206,605	$ 231,838	$ 272,734	$ 265,738	$ 237,671	$ 986,918	$ 1,007,981	$ 1,040,873
Long-lived assets	101,779				112,226				101,779	112,226	122,947
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									977,942	963,797	968,414
Long-lived assets	97,956				108,334				97,956	108,334	110,571
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,131	19,447	48,216
Long-lived assets	3,222				2,900				3,222	2,900	11,084
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									7,845	24,737	24,243
Long-lived assets	$ 601				$ 992				$ 601	$ 992	$ 1,292