Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 396,613	$ 458,102
Accounts receivable, net of allowance for doubtful accounts of $69 and $1,733, respectively	362,881	468,161
Contract assets	155,546	140,082
Inventories	316,237	309,975
Prepaid expenses and other assets	25,730	27,024
Income taxes receivable	803	206
Total current assets	1,257,810	1,403,550
Property, plant and equipment, net of accumulated depreciation of $464,244 and $460,708, respectively	202,665	210,954
Operating lease right-of-use assets	83,985	0
Goodwill	192,116	192,116
Deferred income taxes	2,269	2,478
Other, net	89,033	90,685
Total assets	1,827,878	1,899,783
Current liabilities:
Current installments of long-term debt	8,744	6,793
Accounts payable	372,106	422,053
Income taxes payable	7,894	10,435
Accrued liabilities	98,916	97,878
Total current liabilities	487,660	537,159
Long-term debt, less current installments	143,115	147,277
Operating lease liabilities	73,878	0
Other long-term liabilities	63,696	68,799
Deferred income taxes	14,479	14,323
Shareholders' equity:
Preferred stock, $0.10 par value; 5,000 shares authorized, none issued	0	0
Common stock, $0.10 par value; 145,000 shares authorized; issued and outstanding - 37,679 and 41,357, respectively	3,768	4,136
Additional paid-in capital	516,663	554,939
Retained earnings	539,743	584,274
Accumulated other comprehensive loss	(15,124)	(11,124)
Total shareholders' equity	1,045,050	1,132,225
Commitments and contingencies
Total liabilities and shareholders' equity	$ 1,827,878	$ 1,899,783