Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 3,996	$ (8,147)	$ 2,693		$ (12,138)
Adjustments to reconcile to net cash provided by operating activities:
Depreciation and amortization			18,001		17,615
Gain on sale of fixed assets			(304)		(584)
Equity-based compensation expense			4,443		4,224
Deferred income taxes			294		601
Non-cash restructuring charges			503		1,409
Goodwill impairment	1,258	0	1,258	[1]	0
Definite-lived intangible asset impairment	957	0	957		0
Impairment of assets held for sale			0		11,946
Gain on sale of businesses			(680)		0
(Gain) loss on foreign currency transactions			(319)		701
Other			983		(190)
Changes in operating assets and liabilities (net of acquisitions):
Receivables net, retainage and contract assets			30,488		(289)
Inventories			6,705		(3,966)
Prepaid expenses and other assets			(821)		6,153
Accounts payable and accrued expenses			(7,650)		(5,887)
Contract liabilities			216		(5,056)
Other operating			3,571		(360)
Net cash provided by operating activities			60,338		14,179
Cash flows from investing activities:
Capital expenditures			(10,576)		(14,328)
Proceeds from sale of fixed assets			557		968
Patent expenditures			(154)		(197)
Sale of businesses, net of cash disposed			3,602		0
Net cash used in investing activities			(6,571)		(13,557)
Cash flows from financing activities:
Proceeds from issuance of common stock upon stock option exercises			0		956
Repurchase of common stock			(5,104)		(25,171)
Distributions to non-controlling interests			(153)		(1,409)
Credit facility amendment fees			(1,995)		0
Payments on notes payable, net			0		(179)
Proceeds from line of credit, net			2,000		7,000
Principal payments on long-term debt			(17,500)		(13,125)
Net cash used in financing activities			(22,752)		(31,928)
Effect of exchange rate changes on cash			(919)		226
Net increase (decrease) in cash, cash equivalents and restricted cash for the period			30,096		(31,080)
Cash, cash equivalents and restricted cash, beginning of year			66,222		84,886	$ 84,886
Cash, cash equivalents and restricted cash, end of period	96,318	53,806	96,318		53,806	66,222
Cash, cash equivalents and restricted cash associated with assets held for sale, end of period	0	(1,709)	0		(1,709)
Cash, cash equivalents and restricted cash, end of period	$ 96,318	$ 52,097	$ 96,318		$ 52,097	$ 66,222

[1] During the second quarter of 2020, the Company recorded a $1.3 million goodwill impairment related to restructuring activities in Energy Services (see Note 4).