Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net Income	$ 32,461	$ 9,035	$ 20,077
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by Operating Activities
Depreciation and amortization	28,305	25,296	22,845
Non-cash operating lease cost	2,669	0	0
Property and equipment impairment due to restructuring	0	6,207	3,607
Stock-based compensation expense	7,161	5,040	4,675
Deferred income taxes	(1,830)	2,042	(15,411)
Provision for doubtful accounts	186	267	373
Noncash loss on extinguishment of debt	180	926	0
Other	942	11,659	(1,182)
Changes in Assets and Liabilities:
Accounts receivable	2,380	7,495	2,720
Contract assets	(20,005)	(86,665)	0
Inventories	(8,491)	23,243	(533)
Production cost of contracts	(1,079)	(1,569)	(267)
Other assets	1,358	1,881	40
Accounts payable	11,620	18,496	(4,015)
Contract liabilities	(2,628)	17,145	0
Accrued and other liabilities	(2,198)	5,739	2,505
Net Cash Provided by Operating Activities	51,031	46,237	35,434
Cash Flows from Investing Activities
Purchases of property and equipment	(18,290)	(17,617)	(27,610)
Proceeds from sale of assets	3	396	913
Insurance recoveries related to property and equipment	0	0	288
Payments for acquisition of Lightning Diversion Systems, LLC, net of cash acquired	0	0	(59,798)
Payments for acquisition of Certified Thermoplastics Co., LLC, net of cash acquired	0	(30,712)	0
Payments for acquisition of Nobles Worldwide, Inc. net of cash acquired	(76,647)	0	0
Net Cash Used in Investing Activities	(94,934)	(47,933)	(86,207)
Cash Flows from Financing Activities
Borrowings from senior secured revolving credit facility	298,400	296,400	395,900
Repayment of senior secured revolving credit facility	(298,400)	(354,500)	(337,800)
Borrowings from term loans	140,000	240,000	0
Repayments of term loans	(63,000)	(167,000)	(10,000)
Repayments of other debt	(169)	0	(3)
Debt issuance costs	(1,135)	(3,541)	0
Net cash paid from issuance of common stock under stock plans	(2,472)	(1,550)	(2,606)
Net Cash Provided by Financing Activities	73,224	9,809	45,491
Net Increase (Decrease) in Cash and Cash Equivalents	29,321	8,113	(5,282)
Cash and Cash Equivalents at Beginning of Year	10,263	2,150	7,432
Cash and Cash Equivalents at End of Year	$ 39,584	$ 10,263	$ 2,150