OPERATING SEGMENT DATA - (Operating Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
OPERATING EXPENSES
Salaries, wages, and benefits	$ 350,820	$ 362,209	$ 1,028,552	$ 1,059,542
Rents, purchased transportation, and other costs of services	235,346	218,592	651,131	601,456
Fuel, supplies, and expenses	75,716	52,461	226,666	143,068
Depreciation and amortization	25,497	25,793	76,821	76,692
Other	31,815	34,498	93,005	103,488
Restructuring costs	737		2,731
Total consolidated operating expenses	$ 719,931	$ 693,553	$ 2,078,906	$ 1,984,246