Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total net sales	$ 325,453	$ 318,401
Contract assets, net	1,401
Contract liability			$ 2,757
Domestic [Member]
Disaggregation of Revenue [Line Items]
Total net sales	270,076
Domestic [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	185,743
Domestic [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	70,262
Domestic [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	837
Domestic [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	3,513
Domestic [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	231
Domestic [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	3,201
Domestic [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	492
Domestic [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	7,178
Domestic [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	(1,381)
International [Member]
Disaggregation of Revenue [Line Items]
Total net sales	55,377
International [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	33,003
International [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	17,824
International [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	45
International [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,078
International [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	76
International [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,359
International [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	47
International [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,851
International [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	94
Infrastructure Group [Member]
Disaggregation of Revenue [Line Items]
Total net sales	147,094
Infrastructure Group [Member] | Domestic [Member]
Disaggregation of Revenue [Line Items]
Total net sales	134,486
Infrastructure Group [Member] | Domestic [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	85,518
Infrastructure Group [Member] | Domestic [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	41,113
Infrastructure Group [Member] | Domestic [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	837
Infrastructure Group [Member] | Domestic [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,091
Infrastructure Group [Member] | Domestic [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Infrastructure Group [Member] | Domestic [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,624
Infrastructure Group [Member] | Domestic [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	472
Infrastructure Group [Member] | Domestic [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	4,038
Infrastructure Group [Member] | Domestic [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	(207)
Infrastructure Group [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Total net sales	12,608
Infrastructure Group [Member] | International [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	5,914
Infrastructure Group [Member] | International [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	5,062
Infrastructure Group [Member] | International [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	34
Infrastructure Group [Member] | International [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	778
Infrastructure Group [Member] | International [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	61
Infrastructure Group [Member] | International [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	503
Infrastructure Group [Member] | International [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Infrastructure Group [Member] | International [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	256
Infrastructure Group [Member] | International [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Aggregate and Mining Group [Member]
Disaggregation of Revenue [Line Items]
Total net sales	119,067
Aggregate and Mining Group [Member] | Domestic [Member]
Disaggregation of Revenue [Line Items]
Total net sales	83,836
Aggregate and Mining Group [Member] | Domestic [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	63,494
Aggregate and Mining Group [Member] | Domestic [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	17,834
Aggregate and Mining Group [Member] | Domestic [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Aggregate and Mining Group [Member] | Domestic [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	326
Aggregate and Mining Group [Member] | Domestic [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	72
Aggregate and Mining Group [Member] | Domestic [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,410
Aggregate and Mining Group [Member] | Domestic [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	(5)
Aggregate and Mining Group [Member] | Domestic [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,808
Aggregate and Mining Group [Member] | Domestic [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	(1,103)
Aggregate and Mining Group [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Total net sales	35,231
Aggregate and Mining Group [Member] | International [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	22,327
Aggregate and Mining Group [Member] | International [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	10,289
Aggregate and Mining Group [Member] | International [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	11
Aggregate and Mining Group [Member] | International [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	300
Aggregate and Mining Group [Member] | International [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Aggregate and Mining Group [Member] | International [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	856
Aggregate and Mining Group [Member] | International [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	23
Aggregate and Mining Group [Member] | International [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,331
Aggregate and Mining Group [Member] | International [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	94
Energy Group [Member]
Disaggregation of Revenue [Line Items]
Total net sales	59,292
Energy Group [Member] | Domestic [Member]
Disaggregation of Revenue [Line Items]
Total net sales	51,754
Energy Group [Member] | Domestic [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	36,731
Energy Group [Member] | Domestic [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	11,315
Energy Group [Member] | Domestic [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Energy Group [Member] | Domestic [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	2,096
Energy Group [Member] | Domestic [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	159
Energy Group [Member] | Domestic [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	167
Energy Group [Member] | Domestic [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	25
Energy Group [Member] | Domestic [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	1,332
Energy Group [Member] | Domestic [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	(71)
Energy Group [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Total net sales	7,538
Energy Group [Member] | International [Member] | Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	4,762
Energy Group [Member] | International [Member] | Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	2,473
Energy Group [Member] | International [Member] | Equipment Installation Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Energy Group [Member] | International [Member] | Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Energy Group [Member] | International [Member] | Rental Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	15
Energy Group [Member] | International [Member] | Used Equipment Sales [Member]
Disaggregation of Revenue [Line Items]
Total net sales	0
Energy Group [Member] | International [Member] | Extended Warranty Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	24
Energy Group [Member] | International [Member] | Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Total net sales	264
Energy Group [Member] | International [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Total net sales	$ 0