Consolidated Statements of Stockholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at at Dec. 31, 2015	$ 364,157
Balance at (in shares) at Dec. 31, 2015	64,077,140
Stock-based compensation plans
Total comprehensive income (loss)	$ 10,630	$ 8,218	$ 2,412
Balance at at Mar. 31, 2016	$ 408,442
Balance at (in shares) at Mar. 31, 2016	64,068,782