CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
OPERATING ACTIVITIES
Net income	$ 17,068	$ 39,866
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	73,633	65,142
Amortization of intangibles	3,059	3,079
Pension settlement expense	2,267	2,478
Share-based compensation expense	6,151	6,343
Provision for losses on accounts receivable	787	941
Deferred income tax provision (benefit)	14,199	(7,862)
Gain on sale of property and equipment	(2,581)	(1,691)
Changes in operating assets and liabilities:
Receivables	(18,906)	(14,881)
Prepaid expenses	1,108	2,353
Other assets	(3,655)	505
Income taxes	2,583	14,295
Accounts payable, accrued expenses, and other liabilities	(7,786)	9,006
NET CASH PROVIDED BY OPERATING ACTIVITIES	87,927	119,574
INVESTING ACTIVITIES
Purchases of property, plant and equipment, net of financings	(45,774)	(53,644)
Proceeds from sale of property and equipment	7,296	4,115
Purchases of short-term investments	(51,760)	(48,868)
Proceeds from sale of short-term investments	54,027	25,347
Business acquisitions, net of cash acquired	(24,805)	(5,239)
Capitalization of internally developed software	(7,660)	(6,155)
NET CASH USED IN INVESTING ACTIVITIES	(68,676)	(84,444)
FINANCING ACTIVITIES
Borrowings under credit facilities		70,000
Borrowings under accounts receivable securitization program		35,000
Payments on long-term debt	(36,579)	(92,136)
Net change in book overdrafts	(3,829)	2,179
Net change in restricted cash	422	(1)
Deferred financing costs		(824)
Payment of common stock dividends	(6,249)	(4,740)
Purchases of treasury stock	(7,594)	(10,004)
NET CASH USED IN FINANCING ACTIVITIES	(53,829)	(526)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(34,578)	34,604
Cash and cash equivalents at beginning of period	164,973	157,042
CASH AND CASH EQUIVALENTS AT END OF PERIOD	130,395	191,646
NONCASH INVESTING ACTIVITIES
Equipment financed	61,684	51,009
Accruals for equipment received	$ 9,391	$ 7,150