Accrued Expenses and Other Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accrued Expenses
Salaries and wages	$ 81,267	$ 114,446
Deferred compensation	2,197	3,209
Pension benefits	3,681	3,739
Other postretirement benefits	2,094	2,112
Other employee benefits	1,344	7,172
Insurance obligations	135,652	132,246
Environmental liabilities	3,879	3,877
Operating taxes	106,159	92,330
Income taxes	2,854	5,066
Interest	28,020	32,441
Deposits, mainly from customers	60,654	59,388
Deferred revenue	11,624	11,759
Acquisition holdbacks	5,714	3,817
Other	44,508	48,930
Total	489,647	520,532
Non-Current Liabilities
Salaries and wages	0	0
Deferred compensation	40,641	37,093
Pension benefits	445,789	444,657
Other postretirement benefits	26,442	26,889
Other employee benefits	15,967	19,276
Insurance obligations	192,773	189,431
Environmental liabilities	7,360	8,002
Operating taxes	0	0
Income taxes	23,875	22,843
Interest	0	0
Deposits, mainly from customers	5,752	5,929
Deferred revenue	0	0
Acquisition holdbacks	0	2,187
Other	29,495	30,369
Total	788,094	786,676
Total
Salaries and wages	81,267	114,446
Deferred compensation	42,838	40,302
Pension benefits	449,470	448,396
Other postretirement benefits	28,536	29,001
Other employee benefits	17,311	26,448
Insurance obligations	328,425	321,677
Environmental liabilities	11,239	11,879
Operating taxes	106,159	92,330
Income taxes	26,729	27,909
Interest	28,020	32,441
Deposits, mainly from customers	66,406	65,317
Deferred revenue	11,624	11,759
Acquisition holdbacks	5,714	6,004
Other	74,003	79,299
Total	$ 1,277,741	$ 1,307,208