Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accrued Expenses
Salaries and wages	$ 101,036	$ 114,446
Deferred compensation	2,120	3,209
Pension benefits	3,644	3,739
Other postretirement benefits	2,084	2,112
Other employee benefits	9,059	7,172
Insurance obligations	134,407	132,246
Environmental liabilities	3,836	3,877
Operating taxes	95,311	92,330
Income taxes	2,782	5,066
Interest	32,460	33,509
Deposits, mainly from customers	65,995	59,388
Deferred revenue	13,377	11,759
Acquisition holdbacks	2,134	3,817
Other	42,953	41,009
Total	511,198	513,679
Non-Current Liabilities
Salaries and wages	0	0
Deferred compensation	39,221	37,093
Pension benefits	440,800	444,657
Other postretirement benefits	25,440	26,889
Other employee benefits	9,360	19,276
Insurance obligations	202,258	189,431
Environmental liabilities	7,177	8,002
Operating taxes	0	0
Income taxes	23,620	22,843
Interest	0	0
Deposits, mainly from customers	6,193	5,929
Deferred revenue	0	0
Acquisition holdbacks	0	2,187
Other	26,346	27,035
Total	780,415	783,342
Total
Salaries and wages	101,036	114,446
Deferred compensation	41,341	40,302
Pension benefits	444,444	448,396
Other postretirement benefits	27,524	29,001
Other employee benefits	18,419	26,448
Insurance obligations	336,665	321,677
Environmental liabilities	11,013	11,879
Operating taxes	95,311	92,330
Income taxes	26,402	27,909
Interest	32,460	33,509
Deposits, mainly from customers	72,188	65,317
Deferred revenue	13,377	11,759
Acquisition holdbacks	2,134	6,004
Other	69,299	68,044
Total	$ 1,291,613	$ 1,297,021