Selected Quarterly Financial Data (Unaudited) - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Inventory Valuation Reserves	$ 21,537	$ 20,000	$ 20,100	$ 24,100	$ 21,368	$ 17,500	$ 15,100	$ 6,100	$ 5,700