Summary of Significant Accounting Policies - Recent Accounting Standards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019	Mar. 31, 2018	Jan. 01, 2018
Assets
Accounts receivable, less allowances	$ 382,253	$ 348,943				$ 362,479
Inventories	265,990	241,962				233,054
Prepaid expenses and other current assets	57,184	32,526				47,105
Deferred income taxes	20,474	12,161				11,171
Liabilities
Accrued liabilities	206,782	181,241				194,777
Deferred income taxes	106,559	73,505				73,891
Stockholders’ equity
Retained earnings	1,363,772	1,206,723				1,211,018
Accumulated other non-owner changes to equity	(190,500)	(106,399)	$ (200,828)
Consolidated Statement of Income
Net sales	1,495,889	1,436,499	1,230,754
Cost of sales	963,524	943,779	788,727
Operating profit	231,764	206,451	194,296
Income before income taxes	207,495	195,699	182,621
Income taxes	41,309	136,284	47,020
Net income	166,186	59,415	135,601
Other expense (income), net	7,428	(3,819)	(208)
Facility Closing [Member]
Consolidated Statement of Income
Curtailment gain		(7,217)
Settlement gain (loss)		(230)
Pension Plan [Member]
Consolidated Statement of Income
Curtailment gain	0	(7,217)	0
Settlement gain (loss)	0	(119)	$ 0
Pension Plan [Member] | Facility Closing [Member]
Consolidated Statement of Income
Curtailment gain	(7,217)
Settlement gain (loss)	(230)
Accounting Standards Update 2017-07 [Member]
Consolidated Statement of Income
Other expense (income), net		(3,827)
Accounting Standards Update 2018-02 [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member]
Stockholders’ equity
Retained earnings					$ 19,331
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Assets
Accounts receivable, less allowances	366,870	348,943
Inventories	273,712	241,962
Prepaid expenses and other current assets	45,340
Deferred income taxes	21,056	12,161
Liabilities
Accrued liabilities	191,292	181,241
Deferred income taxes	106,163	73,505
Stockholders’ equity
Retained earnings	1,360,727	$ 1,206,723
Accumulated other non-owner changes to equity	(190,161)
Consolidated Statement of Income
Net sales	1,498,662
Cost of sales	964,657
Operating profit	233,404
Income before income taxes	209,135
Income taxes	41,699
Net income	167,436
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Assets
Accounts receivable, less allowances	15,383					13,536
Inventories	(7,722)					(8,908)
Prepaid expenses and other current assets	11,844					14,579
Deferred income taxes	(582)					(990)
Liabilities
Accrued liabilities	15,490					13,536
Deferred income taxes	396					386
Stockholders’ equity
Retained earnings	3,045					$ 4,295
Accumulated other non-owner changes to equity	(339)
Consolidated Statement of Income
Net sales	(2,773)
Cost of sales	(1,133)
Operating profit	(1,640)
Income before income taxes	(1,640)
Income taxes	(390)
Net income	$ (1,250)
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member]
Consolidated Statement of Income
Lease liabilities				$ 30,000