Segment Information (Segment Information 1) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Commissions	$ 445,734us-gaap_BrokerageCommissionsRevenue	$ 394,414us-gaap_BrokerageCommissionsRevenue	$ 326,132us-gaap_BrokerageCommissionsRevenue
Series A Preferred Stock
Segment Reporting Information [Line Items]
Commissions	5,148
Series A Preferred Stock \| Ladenburg
Segment Reporting Information [Line Items]
Commissions	4,240
Series A Preferred Stock \| Independent brokerage and advisory services
Segment Reporting Information [Line Items]
Commissions	908
Employee brokerage commission expenses \| Series A Preferred Stock
Segment Reporting Information [Line Items]
Commissions	2,603
Employee brokerage commission expenses \| Series A Preferred Stock \| Ladenburg
Segment Reporting Information [Line Items]
Commissions	$ 2,545