Summary of Significant Accounting Policies - New Guidance (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	$ 254,394	$ 257,425	$ 265,866
Inventories	196,896	170,819	165,336
Deferred tax liabilities	37,486	35,386	31,580
Retained earnings	148,802	$ 116,611	$ 123,375
Accounting Standards Update 2014-09 [Member] | Difference between revenue guidance in effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	(8,441)
Inventories	5,483
Deferred tax liabilities	(679)
Retained earnings	(2,279)
Accounting Standards Update 2016-16 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Receivables, net	0
Inventories	0
Deferred tax liabilities	4,485
Retained earnings	$ (4,485)