Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accrued Expenses
Salaries and wages	$ 72,482	$ 99,032
Deferred compensation	2,621	2,252
Pension benefits	3,823	3,790
Other postretirement benefits	1,636	1,624
Other employee benefits	12,120	8,956
Insurance obligations	149,258	157,014
Environmental liabilities	3,862	3,791
Operating taxes	101,350	101,649
Income taxes	824	3,378
Interest	32,712	31,218
Deposits, mainly from customers	64,628	61,869
Deferred revenue	14,655	13,038
Restructuring liabilities	7,526	12,333
Other	38,803	43,408
Total	506,300	543,352
Non-Current Liabilities
Salaries and wages	0	0
Deferred compensation	40,748	41,691
Pension benefits	472,253	484,892
Other postretirement benefits	20,209	20,002
Other employee benefits	3,135	9,706
Insurance obligations	209,376	213,256
Environmental liabilities	6,394	6,554
Operating taxes	0	0
Income taxes	23,270	22,366
Interest	0	0
Deposits, mainly from customers	4,974	5,085
Deferred revenue	0	0
Restructuring liabilities	0	0
Other	26,202	26,043
Total	806,561	829,595
Total
Salaries and wages	72,482	99,032
Deferred compensation	43,369	43,943
Pension benefits	476,076	488,682
Other postretirement benefits	21,845	21,626
Other employee benefits	15,255	18,662
Insurance obligations	358,634	370,270
Environmental liabilities	10,256	10,345
Operating taxes	101,350	101,649
Income taxes	24,094	25,744
Interest	32,712	31,218
Deposits, mainly from customers	69,602	66,954
Deferred revenue	14,655	13,038
Restructuring liabilities	7,526	12,333
Other	65,005	69,451
Total	$ 1,312,861	$ 1,372,947