Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accrued Expenses
Salaries and wages	$ 87,558	$ 99,032
Deferred compensation	2,725	2,252
Pension benefits	3,822	3,790
Other postretirement benefits	1,637	1,624
Other employee benefits	18,404	8,956
Insurance obligations	139,959	157,014
Environmental liabilities	3,997	3,791
Operating taxes	97,187	101,649
Income taxes	448	3,378
Interest	31,369	31,218
Customer deposits	63,272	61,869
Deferred revenue	16,738	13,038
Restructuring liabilities	3,489	12,333
Other	37,912	43,408
Total	508,517	543,352
Non-Current Liabilities
Salaries and wages	0	0
Deferred compensation	42,378	41,691
Pension benefits	482,187	484,892
Other postretirement benefits	19,677	20,002
Other employee benefits	4,290	9,706
Insurance obligations	218,058	213,256
Environmental liabilities	6,333	6,554
Operating taxes	0	0
Income taxes	24,110	22,366
Interest	0	0
Customer deposits	4,791	5,085
Deferred revenue	0	0
Restructuring liabilities	0	0
Other	26,357	26,043
Total	828,181	829,595
Total
Salaries and wages	87,558	99,032
Deferred compensation	45,103	43,943
Pension benefits	486,009	488,682
Other postretirement benefits	21,314	21,626
Other employee benefits	22,694	18,662
Insurance obligations	358,017	370,270
Environmental liabilities	10,330	10,345
Operating taxes	97,187	101,649
Income taxes	24,558	25,744
Interest	31,369	31,218
Customer deposits	68,063	66,954
Deferred revenue	16,738	13,038
Restructuring liabilities	3,489	12,333
Other	64,269	69,451
Total	$ 1,336,698	$ 1,372,947