Income Taxes - A reconciliation of the beginning and ending gross unrecognized tax benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 5,752	$ 6,150	$ 6,016
Foreign currency translation	(478)	(398)	134
Balance at end of year	$ 5,274	$ 5,752	$ 6,150