Business Combinations - HD Vest Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Excess of purchase price over net assets acquired, allocated to goodwill	$ 548,959	$ 188,541
HD Vest [Member]
Business Acquisition [Line Items]
Tangible assets acquired, including cash acquired of $38,874	77,181
Business combination, cash acquired	38,874
Liabilities assumed	(21,845)
Identifiable net assets acquired	55,336
Business combination, intangible assets other than goodwill	323,700
Cash paid	610,500
Plus: non-controlling interest	15,038
Less: escrow receivable	(20,000)
Purchase price	611,938
Less: identifiable net assets acquired	(55,336)
Less: fair value of intangible assets acquired	(323,700)
Plus: deferred tax liability related to intangible assets	123,484
Excess of purchase price over net assets acquired, allocated to goodwill	356,386
HD Vest [Member] | Notes payable, other payables [Member] | President [Member]
Business Acquisition [Line Items]
Plus: promissory note	6,400
HD Vest [Member] | Advisor relationships [Member]
Business Acquisition [Line Items]
Business combination, intangible assets other than goodwill	240,300
Less: fair value of intangible assets acquired	(240,300)
HD Vest [Member] | Sponsor Relationships [Member]
Business Acquisition [Line Items]
Business combination, intangible assets other than goodwill	16,500
Less: fair value of intangible assets acquired	(16,500)
HD Vest [Member] | Curriculum [Member]
Business Acquisition [Line Items]
Business combination, intangible assets other than goodwill	800
Less: fair value of intangible assets acquired	(800)
HD Vest [Member] | Developed Technology Rights [Member]
Business Acquisition [Line Items]
Business combination, intangible assets other than goodwill	13,600
Less: fair value of intangible assets acquired	(13,600)
HD Vest [Member] | Trade name [Member]
Business Acquisition [Line Items]
Business combination, intangible assets other than goodwill	52,500
Less: fair value of intangible assets acquired	$ (52,500)