Contingencies - Narrative (Details) - USD ($)					6 Months Ended
	Jan. 27, 2017	Feb. 17, 2015	Feb. 09, 2015	Jan. 27, 2015	Jun. 30, 2015	Jun. 30, 2014
Loss Contingencies [Line Items]
Litigation Settlement, Expense						$ 20,000,000
Minimum estimated range of aggregate loss for legal proceedings					$ 0
Maximum estimated range of aggregate loss for legal proceedings					35,000,000
Company purchased and holds auction rate securities					107,600,000
Amount of ARS committed to purchase from clients					16,700,000
Purchase Commitments Outstanding, Auction Rate Securities Related to Settlements with Regulators					5,000,000
Eligible investor subject to future buyback potential additional losses related to valuation adjustments					85,300,000
Eligible Investor Subject To Future Buyback Potential Additional Losses Related To Valuation Adjustments					$ 0
Period of auction rates security to be purchased from rendering of the award					30 days
SEC [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount				$ 10,000,000
Payments for Legal Settlements		$ 5,000,000
SEC [Member] | Disgorgement [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount				4,200,000
SEC [Member] | Prejudgment Interest [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount				753,500
SEC [Member] | Civil Penalties [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount				5,100,000
United States Department of the Treasury [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount				$ 10,000,000
Payments for Legal Settlements			$ 5,000,000
Forecast [Member] | SEC [Member]
Loss Contingencies [Line Items]
Payments for Legal Settlements	$ 5,000,000