CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 47,642	$ 116,262
Accounts receivable, net of allowance for doubtful accounts of $5,577 in 2019 and $4,813 in 2018	358,002	323,533
Inventories	118,606	130,083
Income taxes receivable	4,674	35,832
Prepaid expenses	8,154	9,766
Other current assets	3,049	3,462
Total current assets	540,127	618,938
Property, plant and equipment, less accumulated depreciation of $1,669,168 in 2019 and $1,633,827 in 2018	574,858	517,982
Operating lease right-of-use assets	42,727
Goodwill	32,150	32,150
Other assets	34,105	30,510
Total assets	1,223,967	1,199,580
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	122,766	103,401
Accrued payroll and related expenses	22,981	25,715
Accrued insurance expenses	7,350	6,183
Accrued state, local and other taxes	5,834	3,081
Income taxes payable	1,059	4,706
Current portion of operating lease liabilities	12,181
Other accrued expenses	213	151
Total current liabilities	172,384	143,237
Long-term accrued insurance expenses	14,280	12,072
Long-term pension liabilities	33,675	29,638
Deferred income taxes	47,823	60,375
Long-term operating lease liabilities	31,624
Other long-term liabilities	2,506	3,839
Total liabilities	302,292	249,161
Common stock	21,458	21,454
Capital in excess of par value	0	0
Retained earnings	920,917	947,711
Accumulated other comprehensive loss	(20,700)	(18,746)
Total stockholders' equity	921,675	950,419
Total liabilities and stockholders' equity	$ 1,223,967	$ 1,199,580