Income Taxes (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of income tax provision (benefit) to the amount computed by multiplying book income/(loss) before income taxes by federal income tax rate
Tax at statutory rate									$ 8,255	$ (436)	$ 9,861
Permanent differences									844	4,534	572
State taxes, net of federal benefit									1,397	1,086	1,067
Effect of foreign tax rates									49	8	(71)
Uncertain tax positions										(8,104)
Current year adjustment to deferred taxes									3,960
Recognition of tax credits									(1,699)	(432)	(903)
Other									(25)	(276)	174
Income tax expense before change in valuation allowance									12,781	(3,620)	10,700
Change in valuation allowance									(3,960)
Income tax expense (benefit)	4,462	2,448	2,065	(154)	(10,140)	2,504	2,801	1,215	8,821	(3,620)	10,700
Taxes paid for United States federal, state and foreign income taxes									$ 1,331	$ 3,651	$ 7,507