Acquisition (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Dec. 21, 2012 D and R Technology [Member] Estimated Fair Values [Member]	Dec. 21, 2012 D and R Technology [Member] Estimated Fair Values [Member] In-process research and development [Member]
Summary of the estimated fair values of the assets acquired and the liabilities assumed
Current assets			$ 13,839
Property, plant and equipment			8,635
Goodwill	35,156	35,156	26,991
Amortizable intangible assets			18,330
In-process research and development				500
Other assets			678
Fair value of assets acquired			68,973
Less fair value of liabilities acquired			(5,473)
Net cash paid			$ 63,500