Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities
Net income	$ 29,174	$ 32,461	$ 9,035
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation and amortization	28,850	28,305	25,296
Non-cash operating lease cost	3,157	2,669	0
Property and equipment impairment due to restructuring	0	0	6,207
Stock-based compensation expense	9,299	7,161	5,040
Deferred income taxes	327	(1,830)	2,042
Provision for credit losses	231	186	267
Noncash loss on extinguishment of debt	0	180	926
Insurance recoveries related to loss on operating assets	8,546	0	0
Other	826	942	11,659
Changes in Assets and Liabilities:
Accounts receivable	8,877	2,380	7,495
Contract assets	(47,358)	(20,005)	(86,665)
Inventories	(20,183)	(8,491)	23,243
Production cost of contracts	(1,488)	(1,079)	(1,569)
Other assets	(212)	1,358	1,881
Accounts payable	(19,714)	11,620	18,496
Contract liabilities	13,747	(2,628)	17,145
Operating lease liabilities	(2,953)	(2,713)	0
Accrued and other liabilities	1,485	515	5,739
Net Cash Provided by Operating Activities	12,611	51,031	46,237
Cash Flows from Investing Activities
Purchases of property and equipment	(12,510)	(18,290)	(17,617)
Proceeds from sale of assets	5	3	396
Insurance recoveries related to property and equipment	4,954	0	0
Life insurance proceeds	1,889	0	0
Payments for acquisition of Certified Thermoplastics Co., LLC, net of cash acquired	0	0	(30,712)
Payments for acquisition of Nobles Worldwide, Inc. net of cash acquired	0	(76,647)	0
Post closing cash received from the acquisition of Nobles Worldwide, Inc., net	190	0	0
Net Cash Used in Investing Activities	(5,472)	(94,934)	(47,933)
Cash Flows from Financing Activities
Borrowings from senior secured revolving credit facility	65,900	298,400	296,400
Repayments of senior secured revolving credit facility	(40,900)	(298,400)	(354,500)
Borrowings from term loans	0	140,000	240,000
Repayments of term loans	(14,362)	(63,000)	(167,000)
Repayments of other debt	(288)	(169)	0
Debt issuance costs	0	(1,135)	(3,541)
Net cash paid upon issuance of common stock under stock plans	(607)	(2,472)	(1,550)
Net Cash Provided by Financing Activities	9,743	73,224	9,809
Net Increase in Cash and Cash Equivalents	16,882	29,321	8,113
Cash and Cash Equivalents at Beginning of Year	39,584	10,263	2,150
Cash and Cash Equivalents at End of Year	$ 56,466	$ 39,584	$ 10,263