Acquisitions and Divestitures - Allocation of Acquisition Costs to Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2016	Jul. 01, 2016	Mar. 16, 2016
Business Acquisition [Line Items]
Goodwill	$ 1,697,955	$ 1,704,158	$ 1,632,592
Intangible assets				$ 217,700
Acquisitions 2016
Business Acquisition [Line Items]
Accounts receivable			29,580
Inventory			61,562
Other current assets, net of cash acquired			5,512
Property, plant and equipment			23,427
Goodwill			287,996
Intangible assets			217,677
Deferred income taxes			3,928
Total assets acquired			629,682
Current liabilities			(23,902)
Deferred income taxes			(72,607)
Other noncurrent liabilities			(23,172)
Net assets acquired			$ 510,001
Akron Brass
Business Acquisition [Line Items]
Accounts receivable						$ 14,523
Inventory						29,157
Other current assets, net of cash acquired						446
Property, plant and equipment						12,195
Goodwill						124,643
Intangible assets						90,400
Deferred income taxes						0
Total assets acquired						271,364
Current liabilities						(7,081)
Deferred income taxes						(36,439)
Other noncurrent liabilities						(6,445)
Net assets acquired						$ 221,399
AWG Fittings
Business Acquisition [Line Items]
Accounts receivable					$ 5,867
Inventory					11,766
Other current assets, net of cash acquired					565
Property, plant and equipment					6,595
Goodwill					22,055
Intangible assets					10,279
Deferred income taxes					3,928
Total assets acquired					61,055
Current liabilities					(5,117)
Deferred income taxes					0
Other noncurrent liabilities					(8,444)
Net assets acquired					$ 47,494
SFC-Koenig
Business Acquisition [Line Items]
Accounts receivable				9,190
Inventory				20,639
Other current assets, net of cash acquired				4,501
Property, plant and equipment				4,637
Goodwill				141,298
Intangible assets				116,998
Deferred income taxes				0
Total assets acquired				297,263
Current liabilities				(11,704)
Deferred income taxes				(36,168)
Other noncurrent liabilities				(8,283)
Net assets acquired				$ 241,108