Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 395,316	$ 458,102
Accounts receivable, net of allowance for doubtful accounts of $69 and $1,733, respectively	405,358	468,161
Contract assets	157,025	140,082
Inventories	315,563	309,975
Prepaid expenses and other assets	24,007	27,024
Income taxes receivable	660	206
Total current assets	1,297,929	1,403,550
Property, plant and equipment, net of accumulated depreciation of $459,222 and $460,708, respectively	203,796	210,954
Operating lease right-of-use assets	81,159	0
Goodwill	192,116	192,116
Deferred income taxes	2,269	2,478
Other, net	91,661	90,685
Total assets	1,868,930	1,899,783
Current liabilities:
Current installments of long-term debt	8,706	6,793
Accounts payable	371,732	422,053
Income taxes payable	11,563	10,435
Accrued liabilities	98,235	97,878
Total current liabilities	490,236	537,159
Long-term debt, less current installments	145,205	147,277
Operating lease liabilities	70,859	0
Other long-term liabilities	69,537	68,799
Deferred income taxes	14,368	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 - 39,169 and 41,357, respectively	3,917	4,136
Additional paid-in capital	530,261	554,939
Retained earnings	557,804	584,274
Accumulated other comprehensive loss	(13,257)	(11,124)
Total shareholders' equity	1,078,725	1,132,225
Total liabilities and shareholders' equity	$ 1,868,930	$ 1,899,783