Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Asset
Expense accruals	$ 23,300	$ 24,538
Inventories	6,611	5,588
Provision for receivables	1,015	1,049
Operating loss carryforwards	80,178	77,151
Foreign tax credit carryforwards	26,347	19,199
Capital loss carryforwards	18,163	2,102
Pensions	74,506	66,675
Currency adjustments	17,597	28,589
Unit adjustment liability	0	29,491
Post-retirement benefits	760	869
Stock based compensation	5,812	4,790
Other	7,206	3,656
Subtotal	261,495	263,697
Valuation allowance	(146,097)	(110,680)
Total deferred income taxes	115,398	153,017
Liability
Depreciation and amortization	10,089	11,474
Deferred revenue	1,852	1,904
Equity investment in Infrastructure strategic venture	0	10,688
Total deferred income taxes	11,941	24,066
Deferred Tax Assets, Net, Classification [Abstract]
Other current assets	27,415	38,899
Other assets	78,944	102,914
Other current liabilities	281	767
Deferred income taxes	$ 2,621	$ 12,095