Commitments and Contingencies - Legal Narrative (Details)				1 Months Ended	0 Months Ended				12 Months Ended	0 Months Ended			1 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended		12 Months Ended	0 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2014 Potential Claim for Pension Advisory Services [Member] USD ($)	Apr. 30, 2014 Potential Claim for Pension Advisory Services [Member] GBP (£)	May 31, 2010 Opry Mills Mall Limited Partnership [Member] USD ($)	Dec. 12, 2012 Mazeikiu Nafta [Member] USD ($)	Dec. 02, 2014 International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] USD ($)	Dec. 02, 2014 International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] CHF	Jun. 01, 2007 International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] CHF	Dec. 31, 2014 International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] USD ($)	Dec. 02, 2014 International Road Transport Union [Member] Litigation USD Denominated Award [Member] USD ($)	Jun. 01, 2007 International Road Transport Union [Member] Litigation USD Denominated Award [Member] USD ($)	Jun. 01, 2007 International Road Transport Union [Member] Litigation Expenses and Interest [Member] USD ($)	Jan. 31, 2014 Northrop Grumman Corporation [Member] USD ($)	Jan. 02, 2014 Philips [Member] GBP (£)	Dec. 31, 2014 Philips [Member] USD ($)	Oct. 27, 2014 Mazeikiu Nafta [Member] USD ($)	Dec. 27, 2012 Versicherung Aktiengesellschaft [Member] Litigation Foreign Currency Denominated Award [Member] EUR (€)	Dec. 31, 2014 Versicherung Aktiengesellschaft [Member] Litigation Foreign Currency Denominated Award [Member] USD ($)	Jan. 26, 2015 Subsequent Event [Member] International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] USD ($)	Jan. 26, 2015 Subsequent Event [Member] International Road Transport Union [Member] Litigation Foreign Currency Denominated Award [Member] CHF	Jan. 26, 2015 Subsequent Event [Member] International Road Transport Union [Member] Litigation USD Denominated Award [Member] USD ($)
Loss Contingencies [Line Items]
Range of possible loss, minimum	$ 0
Range of possible loss, maximum	600,000,000
Value of damages sought				200,000,000	125,000,000			46,000,000	47,000,000		3,000,000	30,000,000	340,000,000	189,000,000	294,000,000		183,000,000	223,000,000
Damages awarded excluding interest and costs						17,000,000	16,800,000			3,100,000
Damages awarded						28,000,000	27,900,000			5,000,000
Legal length of trial																11 days
Amount of coverage for damages contended by the insurers				50,000,000
Difference amount of damages sought by the client				150,000,000
Litigation settlement																5,000,000			13,000,000	13,000,000	4,700,000
Settlement agreement terms maximum liability																			10,000,000	9,500,000	75,000
Estimate of possible loss		$ 70,000,000	£ 45,000,000