Business Segment and Foreign Operations - Long-lived Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Long-Lived Assets [Line Items]
Long-lived tangible assets	$ 81,606	$ 80,849
United States [Member]
Long-Lived Assets [Line Items]
Long-lived tangible assets	5,716	4,662
People's Republic of China [Member]
Long-Lived Assets [Line Items]
Long-lived tangible assets	70,619	72,957
All Other Countries [Member]
Long-Lived Assets [Line Items]
Long-lived tangible assets	$ 5,271	$ 3,230