Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net income	$ 6,493	$ 5,509
Other comprehensive income (loss):
Foreign currency translation adjustment	3,078	(3,800)
Reclassification of loss on cash flow hedges, net of tax	0	143
Adjustment to retirement benefit liability, net of tax	(1)	2
Adjustment to post-retirement health care liability, net of tax	38	37
Other comprehensive income (loss)	3,115	(3,618)
Total comprehensive income	$ 9,608	$ 1,891