Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Jun. 30, 2020
Current assets:
Cash and cash equivalents	$ 93,481	$ 100,036
Accounts receivable, less allowances (December 31, 2020—$853 and June 30, 2020—$905)	151,068	160,671
Costs and estimated earnings in excess of billings on uncompleted contracts	41,398	59,548
Inventories	6,764	6,460
Income taxes receivable	4,287	3,919
Other current assets	7,769	4,526
Total current assets	304,767	335,160
Property, plant and equipment at cost:
Land and buildings	43,243	42,695
Construction equipment	94,893	94,154
Transportation equipment	52,182	55,864
Office equipment and software	42,143	39,356
Construction in progress	2,065	4,427
Property, plant and equipment at cost, gross	234,526	236,496
Accumulated depreciation	(158,774)	(155,748)
Property, plant and equipment at cost, net	75,752	80,748
Operating lease right-of-use assets	18,308	21,375
Goodwill	60,605	60,369
Other intangible assets, net of accumulated amortization	7,743	8,837
Deferred income taxes	6,815	5,988
Other assets	5,920	4,833
Total assets	479,910	517,310
Current liabilities:
Accounts payable	51,269	73,094
Billings on uncompleted contracts in excess of costs and estimated earnings	62,244	63,889
Accrued wages and benefits	16,373	16,205
Accrued insurance	7,795	7,301
Operating lease liabilities	5,359	7,568
Other accrued expenses	7,087	7,890
Total current liabilities	150,127	175,947
Deferred income taxes	75	61
Operating lease liabilities	17,521	19,997
Borrowings under senior secured revolving credit facility	0	9,208
Other liabilities	7,898	4,208
Total liabilities	175,621	209,421
Commitments and contingencies
Stockholders' equity:
Common stock—$.01 par value; 60,000,000 shares authorized; 27,888,217 shares issued as of December 31, 2020 and June 30, 2020; 26,502,960 and 26,141,528 shares outstanding as of December 31, 2020 and June 30, 2020	279	279
Additional paid-in capital	133,957	138,966
Retained earnings	198,774	206,402
Accumulated other comprehensive loss	(7,150)	(8,373)
Stockholders' equity	325,860	337,274
Less: Treasury stock, at cost — 1,385,257 shares as of December 31, 2020, and 1,746,689 shares as of June 30, 2020	(21,571)	(29,385)
Total Stockholders' Equity	304,289	307,889
Total liabilities and stockholders’ equity	$ 479,910	$ 517,310