Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,669	$ 933	$ 19,317	$ 16,562
Foreign currency translation adjustments	(533)	3,727	195	(8,230)
Net change in:
Deferred gains (losses) on cash flow hedges, net of taxes of $(408), $136, $(381) and $(34), respectively	1,080	(395)	1,001	46
Unrecognized retirement obligations, net of taxes of $(1,513), $(2,263), $(2,928) and $(4,576), respectively	2,479	3,773	4,795	7,600
Other comprehensive income (loss)	3,026	7,105	5,991	(584)
Comprehensive income	$ 7,695	$ 8,038	$ 25,308	$ 15,978