- Fair Value of Assets Acquired, Summary (Details) - USD ($) $ in Thousands	1 Months Ended													12 Months Ended			24 Months Ended
	Nov. 30, 2018	Sep. 30, 2018	Jun. 30, 2018	May 31, 2018	Apr. 30, 2018	Mar. 31, 2018	Feb. 28, 2018	Dec. 31, 2017	Nov. 30, 2017	Sep. 30, 2017	Jul. 31, 2017	Apr. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill								$ 208,044						$ 319,349	$ 281,734	$ 208,044	$ 319,349
Contingent consideration liability														9,600	13,800		9,600
Business acquisitions														55,953	343,347	251,851
Metal Moulding Corporation
Business Acquisition [Line Items]
Consideration transferred							$ 19,900
Trade receivables															1,463
Inventories															2,324
Property, plant and equipment															2,085
Prepaid expenses & other															0
Intangible assets															8,540
Goodwill															7,668
Less: Total liabilities															827
Less: Deferred taxes															0
Total net assets acquired															21,253
Contingent consideration liability															1,400
Business acquisitions															19,900
Aluminum Metals Company
Business Acquisition [Line Items]
Consideration transferred							$ 17,800
Trade receivables															3,942
Inventories															5,623
Property, plant and equipment															2,321
Prepaid expenses & other															39
Intangible assets															6,550
Goodwill															1,755
Less: Total liabilities															2,463
Less: Deferred taxes															0
Total net assets acquired															17,767
Indiana Marine Products
Business Acquisition [Line Items]
Consideration transferred						$ 18,600
Trade receivables															1,943
Inventories															4,286
Property, plant and equipment															1,463
Prepaid expenses & other															13
Intangible assets															12,920
Goodwill															8,803
Less: Total liabilities															2,930
Less: Deferred taxes															0
Total net assets acquired															26,498
Contingent consideration liability															7,900
Business acquisitions															18,600
Collins & Company
Business Acquisition [Line Items]
Consideration transferred						$ 40,000
Trade receivables															2,830
Inventories															9,903
Property, plant and equipment															1,188
Prepaid expenses & other															5
Intangible assets															18,430
Goodwill															10,237
Less: Total liabilities															2,586
Less: Deferred taxes															0
Total net assets acquired															40,007
Dehco Inc
Business Acquisition [Line Items]
Consideration transferred					$ 52,800
Trade receivables															4,771
Inventories															16,923
Property, plant and equipment															13,755
Prepaid expenses & other															208
Intangible assets															13,950
Goodwill															6,580
Less: Total liabilities															3,392
Less: Deferred taxes															0
Total net assets acquired															52,795
Dowco Inc.
Business Acquisition [Line Items]
Consideration transferred				$ 56,300
Trade receivables															4,053
Inventories															4,498
Property, plant and equipment															8,566
Prepaid expenses & other															1,240
Intangible assets															28,435
Goodwill															13,732
Less: Total liabilities															4,178
Less: Deferred taxes															0
Total net assets acquired															56,346
Marine Accessories Corporation
Business Acquisition [Line Items]
Consideration transferred			$ 57,000
Trade receivables															3,054
Inventories															6,815
Property, plant and equipment															7,003
Prepaid expenses & other															284
Intangible assets															26,190
Goodwill															25,669
Less: Total liabilities															4,227
Less: Deferred taxes															7,767
Total net assets acquired															57,021
Engineered Metals And Composites
Business Acquisition [Line Items]
Trade receivables															623
Inventories															1,678
Property, plant and equipment															1,684
Prepaid expenses & other															0
Intangible assets															17,350
Goodwill															7,483
Less: Total liabilities															987
Less: Deferred taxes															0
Total net assets acquired															27,831
Contingent consideration liability															2,500
Business acquisitions		$ 25,300												100	25,200		25,300
LaSalle Bristol
Business Acquisition [Line Items]
Consideration transferred	$ 51,500
Trade receivables															8,957
Inventories															39,293
Property, plant and equipment															7,670
Prepaid expenses & other															6,560
Intangible assets															12,551
Goodwill															4,520
Less: Total liabilities															28,882
Less: Deferred taxes															(798)
Total net assets acquired															51,467
Medallion
Business Acquisition [Line Items]
Consideration transferred													$ 9,900
Trade receivables								2,233								2,233
Inventories								2,605								2,605
Property, plant and equipment								1,713								1,713
Prepaid expenses & other								118								118
Intangible assets								3,100								3,100
Goodwill								1,342								1,342
Less: Total liabilities								1,200								1,200
Less: Deferred taxes								0								0
Total net assets acquired								9,911								9,911
LPE
Business Acquisition [Line Items]
Consideration transferred												$ 73,300
Trade receivables								5,848								5,848
Inventories								5,162								5,162
Property, plant and equipment								9,225								9,225
Prepaid expenses & other								337								337
Intangible assets								33,275								33,275
Goodwill								39,945								39,945
Less: Total liabilities								6,358								6,358
Less: Deferred taxes								14,140								14,140
Total net assets acquired								73,294								73,294
Wire Design
Business Acquisition [Line Items]
Consideration transferred											$ 10,800
Trade receivables								615								615
Inventories								437								437
Property, plant and equipment								555								555
Prepaid expenses & other								21								21
Intangible assets								5,590								5,590
Goodwill								4,052								4,052
Less: Total liabilities								491								491
Less: Deferred taxes								0								0
Total net assets acquired								10,779								10,779
Baymont
Business Acquisition [Line Items]
Consideration transferred										$ 3,800
Trade receivables								0								0
Inventories								1,174								1,174
Property, plant and equipment								2,067								2,067
Prepaid expenses & other								0								0
Intangible assets								3,166								3,166
Goodwill								1,502								1,502
Less: Total liabilities								69								69
Less: Deferred taxes								0								0
Total net assets acquired								7,840								7,840
Contingent consideration liability								4,000								4,000
Business acquisitions																3,800
Indiana Transport
Business Acquisition [Line Items]
Consideration transferred									$ 58,800
Trade receivables								6,379								6,379
Inventories								0								0
Property, plant and equipment								2,594								2,594
Prepaid expenses & other								1,309								1,309
Intangible assets								31,675								31,675
Goodwill								19,950								19,950
Less: Total liabilities								3,117								3,117
Less: Deferred taxes								0								0
Total net assets acquired								58,790								58,790
LMI
Business Acquisition [Line Items]
Consideration transferred									$ 80,300
Trade receivables								11,205								11,205
Inventories								9,071								9,071
Property, plant and equipment								6,028								6,028
Prepaid expenses & other								449								449
Intangible assets								32,810								32,810
Goodwill								29,241								29,241
Less: Total liabilities								8,471								8,471
Less: Deferred taxes								0								0
Total net assets acquired								80,333								80,333
Nickell
Business Acquisition [Line Items]
Consideration transferred								12,600
Trade receivables								1,784								1,784
Inventories								1,547								1,547
Property, plant and equipment								1,240								1,240
Prepaid expenses & other								0								0
Intangible assets								6,250								6,250
Goodwill								2,331								2,331
Less: Total liabilities								556								556
Less: Deferred taxes								0								0
Total net assets acquired								12,596								12,596
Other
Business Acquisition [Line Items]
Trade receivables								0							473	0
Inventories								250							329	250
Property, plant and equipment								2,668							280	2,668
Prepaid expenses & other								0							13	0
Intangible assets								0							1,667	0
Goodwill								668							919	668
Less: Total liabilities								124							195	124
Less: Deferred taxes								0							0	0
Total net assets acquired								3,462							3,486	3,462
Acquired Entities
Business Acquisition [Line Items]
Trade receivables								28,064						10,115	32,109	28,064	10,115
Inventories								20,246						7,257	91,672	20,246	7,257
Property, plant and equipment								26,090						5,200	46,015	26,090	5,200
Prepaid expenses & other								2,234						103	8,362	2,234	103
Intangible assets								115,866						17,766	146,583	115,866	17,766
Goodwill								99,031						24,088	87,366	99,031	24,088
Less: Total liabilities								20,386						5,699	50,667	20,386	5,699
Less: Deferred taxes								14,140						1,922	6,969	14,140	1,922
Total net assets acquired								$ 257,005						56,908	$ 354,471	$ 257,005	56,908
G.G. Schmitt & Sons, Inc.
Business Acquisition [Line Items]
Consideration transferred														54,300
Contingent consideration liability														$ 2,600			$ 2,600