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Business Segment Information (Reportable Segments) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segments	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments (in segments) \| segments									2
Summarized financial information of the reportable segments
Sales to external customers	$ 1,068,200	$ 996,500	$ 990,100	$ 890,100	$ 986,900	$ 952,700	$ 973,100	$ 920,000	$ 3,944,850	$ 3,832,666	$ 3,660,831
Intersegment sales									0	0	0
Segment operating income (loss)									406,040	247,538	341,135
Depreciation and amortization									104,481	112,473	118,454
Identifiable assets	4,919,642				4,616,277				4,919,642	4,616,277	4,910,474
Capital expenditures									66,170	83,993	61,602
Subtotal—Reportable Segments
Summarized financial information of the reportable segments
Sales to external customers									3,944,850	3,832,666	3,660,831
Intersegment sales									5,464	6,453	5,988
Segment operating income (loss)									541,486	402,197	435,969
Depreciation and amortization									74,422	94,733	104,802
Identifiable assets	4,308,087				4,037,596				4,308,087	4,037,596	4,299,766
Capital expenditures									40,899	55,106	44,784
FPD
Summarized financial information of the reportable segments
Sales to external customers									2,704,445	2,620,488	2,477,738
Intersegment sales									1,833	2,816	970
Segment operating income (loss)									343,514	200,981	112,287
Depreciation and amortization									50,845	68,148	77,524
Identifiable assets	2,974,161				2,768,879				2,974,161	2,768,879	2,981,822
Capital expenditures									26,450	40,648	28,158
FCD
Summarized financial information of the reportable segments
Sales to external customers									1,240,405	1,212,178	1,183,093
Intersegment sales									3,631	3,637	5,018
Segment operating income (loss)									197,972	201,216	323,682
Depreciation and amortization									23,577	26,585	27,278
Identifiable assets	1,333,926				1,268,717				1,333,926	1,268,717	1,317,944
Capital expenditures									14,449	14,458	16,626
Eliminations and All Other
Summarized financial information of the reportable segments
Sales to external customers									0	0	0
Intersegment sales									(5,464)	(6,453)	(5,988)
Segment operating income (loss)									(135,446)	(154,659)	(94,834)
Depreciation and amortization									30,059	17,740	13,652
Identifiable assets	$ 611,555				$ 578,681				611,555	578,681	610,708
Capital expenditures									$ 25,271	$ 28,887	$ 16,818