Accounts Receivable Accounts Receivable (Accounts Receivable) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Trade receivables	$ 334,059	$ 305,363
Allowance for doubtful accounts	(5,674)	(4,904)
Other allowances	(2,644)	(2,019)
Accounts receivable, net	$ 325,741	$ 298,440