Retirement Plans - Schedule of Net Periodic Benefit Cost Not yet Recognized (Details) (United Kingdom Subsidiary, UK Plan, USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
United Kingdom Subsidiary \| UK Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized losses	$ 102,673	$ 87,461

After tax net amount of gain (loss) that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases (decreases) in other comprehensive income as they arise.

No definition available.

Name:	us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesAfterTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant