Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net income	$ 16,989	$ 4,087	$ 23,482	$ 9,596
Other comprehensive income (loss):
Foreign currency translation adjustment	7,753	2,138	10,831	(1,662)
Reclassification of loss on cash flow hedges, net of tax	0	0	0	143
Adjustment to retirement benefit liability, net of tax	(1)	2	(2)	4
Adjustment to post-retirement health care liability, net of tax	38	37	76	74
Other comprehensive income (loss)	7,790	2,177	10,905	(1,441)
Total comprehensive income	$ 24,779	$ 6,264	$ 34,387	$ 8,155