Income Taxes - Net deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets
Compensation and benefits	$ 22,053	$ 24,736
Share-based compensation	5,474
Equity appreciation rights	57,146	62,679
Pension and other postretirement benefits	45,926	39,268
Inventories	9,120	7,011
Accounts receivables	2,942	3,790
Customer sales incentives	3,254	2,761
Transaction costs	3,157	3,601
Other reserves	5,764	6,056
Interest	2,260	5,852
Miscellaneous	1,076	160
Net operating loss and other tax carryforwards	55,936	47,557
Gross deferred tax assets	214,108	203,471
Valuation allowance	(21,726)	(20,771)	$ (13,850)	$ (10,510)
Net deferred tax asset	122,964	125,153
Deferred tax liabilities
Property, plant and equipment	(17,496)	(15,043)
Identifiable intangible assets	(46,701)	(38,075)
Foreign exchange derivative instruments	(4,076)	(3,600)
Miscellaneous	(1,145)	(829)
Total deferred tax liabilities	(69,418)	(57,547)
Net deferred tax asset	$ 192,382	$ 182,700