Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 122,628	$ 129,565	$ 267,705
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	524,177	571,961	581,940
Gain on sale of real estate	(3,302)	0	(108,109)
Amortization of deferred debt issuance costs and premiums	1,640	1,120	1,235
Deferred income taxes	25,931	(13,110)	(42,189)
Loss on debt retirement	8,536	1,512	4,835
Loss (gain) on disposal of fixed assets, net	(1,175)	5,310	(2,648)
Share-based compensation	6,911	5,018	5,145
Other, net	4,394	2,558	(8,143)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(124,140)	80,571	(133,814)
Inventories	10,208	(16,310)	(36,307)
Other current assets	(2,369)	4,329	(2,473)
Other assets	2,253	1,986	(458)
Trade accounts payable	38,670	(43,490)	67,574
Accrued expenses	(33,297)	(78,136)	29,424
Pension and severance obligations	(12,216)	(4,653)	23,881
Net operating lease ROU asset	(127,743)
Operating lease liabilities	131,967
Other non-current liabilities	(9,223)	15,179	(29,331)
Net cash provided by operating activities	563,850	663,410	618,267
Cash flows from investing activities:
Payments for property, plant and equipment	(472,433)	(547,122)	(550,943)
Proceeds from sale of property, plant and equipment	10,117	2,841	141,530
Proceeds from insurance recovery for property, plant and equipment	1,538	1,371	0
Proceeds from foreign exchange forward contracts	13,550	6,754	0
Payments for foreign exchange forward contracts	(15,593)	(5,864)	0
Acquisition of business, net of cash acquired	0	0	(43,771)
Other investing activities	332	4,637	(1,648)
Net cash used in investing activities	(462,489)	(537,383)	(454,832)
Cash flows from financing activities:
Proceeds from revolving credit facilities	272,700	0	75,000
Payments of revolving credit facilities	(272,700)	(75,000)	0
Proceeds from short-term debt	51,434	23,341	77,781
Payments of short-term debt	(52,635)	(46,631)	(70,236)
Proceeds from issuance of long-term debt	975,575	596,226	223,976
Payments of long-term debt	(862,927)	(535,738)	(405,269)
Payments of long-term debt, related party	0	0	(17,837)
Payments for debt issuance costs	(7,027)	(3,796)	(156)
Payments of finance lease obligations	(6,574)
Payments of finance lease obligations		(3,930)	(5,340)
Payment of deferred consideration for purchase of facility	0	0	(3,890)
Proceeds from issuance of stock through share-based compensation plans	11,405	1,050	3,124
Other financing activities	(1,001)	3,855	(2,039)
Net cash provided by (used in) financing activities	108,250	(40,623)	(124,886)
Effect of exchange rate fluctuations on cash, cash equivalents and restricted cash	870	(204)	8,807
Net increase in cash, cash equivalents and restricted cash	210,481	85,200	47,356
Cash, cash equivalents and restricted cash, beginning of period	688,051	602,851	555,495
Cash, cash equivalents and restricted cash, end of period	898,532	688,051	602,851
Cash paid during the period for:
Interest	65,992	77,575	83,808
Income taxes	44,495	63,080	61,878
Non-cash investing and financing activities:
Property, plant and equipment included in capital expenditures payable	77,250	256,070	294,912
Right of use assets acquired through finance lease liabilities	10,835	17,163	929
Right of use assets acquired through operating lease liabilities	$ 60,963	$ 0	$ 0