Income Taxes Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Loss Carryforwards [Line Items]
Current Income Tax Expense (Benefit)	$ 2,370
Unrecognized tax benefits, period increase (decrease)	2,133	68
Income tax expense	4,211	1,604
Document Period End Date	Mar. 31, 2014
UNITED KINGDOM
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, International, Utilized	$ (290)