Basis of Presentation and Significant Accounting Policies - New Guidance (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	$ 264,014	$ 257,425	$ 265,866
Inventories	202,707	170,819	165,336
Deferred tax liabilities	33,347	35,386	31,580
Retained earnings	$ 138,233	$ 116,611	123,375
ASU 2014-09 | Difference between revenue guidance in effect before and after Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net			(8,441)
Inventories			5,483
Deferred tax liabilities			(679)
Retained earnings			(2,279)
ASU 2016-16
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net			0
Inventories			0
Deferred tax liabilities			4,485
Retained earnings			$ (4,485)