CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES
Net income (loss)	$ 9,954	$ (7,407)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	25,352	24,258
Amortization of intangibles	1,134	1,136
Pension settlement expense	654	1,957
Share-based compensation expense	1,870	1,731
Provision for losses on accounts receivable	445	442
Deferred income tax benefit	(2,749)	(4,197)
Gain on sale of property and equipment	(221)	(613)
Changes in operating assets and liabilities:
Receivables	(10,260)	3,345
Prepaid expenses	(2,587)	(5,174)
Other assets	2,732	(3,357)
Income taxes	1,938	(1,205)
Accounts payable, accrued expenses, and other liabilities	3,513	(9,155)
NET CASH PROVIDED BY OPERATING ACTIVITIES	31,775	1,761
INVESTING ACTIVITIES
Purchases of property, plant and equipment, net of financings	(7,177)	(12,273)
Proceeds from sale of property and equipment	1,050	1,692
Purchases of short-term investments	(4,410)	(6,223)
Proceeds from sale of short-term investments	6,245	6,125
Capitalization of internally developed software	(2,164)	(2,440)
NET CASH USED IN INVESTING ACTIVITIES	(6,456)	(13,119)
FINANCING ACTIVITIES
Payments on long-term debt	(16,558)	(17,297)
Net change in book overdrafts	(2,572)	(981)
Payment of common stock dividends	(2,058)	(2,066)
Purchases of treasury stock	(201)
Payments for tax withheld on share-based compensation	(50)	(325)
NET CASH USED IN FINANCING ACTIVITIES	(21,439)	(20,669)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH	3,880	(32,027)
Cash and cash equivalents and restricted cash at beginning of period	120,772	115,242
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	124,652	83,215
NONCASH INVESTING ACTIVITIES
Equipment financed	121	694
Accruals for equipment received	$ 883	$ 440