Other Comprehensive Income (Loss) - Related Tax Effects Allocated to Each Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Equity [Abstract]
Retirement benefits adjustment, before tax amount	$ 143	$ 95
Cumulative translation adjustment, before tax amount	305	(3,008)
Total other comprehensive income (loss), before tax amount	448	(2,913)
Retirement benefits adjustment, tax	(34)	(34)
Cumulative translation adjustment, tax	0	0
Total other comprehensive income (loss), tax	(34)	(34)
Retirement benefits adjustment, after tax amount	109	61
Cumulative translation adjustment, after tax amount	305	(3,008)
Total other comprehensive income (loss)	$ 414	$ (2,947)