Income Taxes Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating Loss Carryforwards [Line Items]
Current Income Tax Expense (Benefit)			$ 3,960
Unrecognized tax benefits, period increase (decrease)			3,866	2,349
Income tax expense	3,326	4,014	7,537	5,618
UNITED KINGDOM
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, International, Utilized			$ (290)