Investment Securities (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Available for sale securities:
Amortized cost	$ 119,741,000	$ 102,286,000
Unrealized gains	6,504,000	5,961,000
Unrealized losses	(27,000)	(957,000)
Fair value	126,218,000	107,290,000
Trading securities:
Fair value	91,134,000	94,058,000
Investment securities	217,352,000	201,348,000
Purchases of trading securities	80,500,000
Sales and maturities of trading securities	62,300,000
Mortgage-backed securities
Available for sale securities:
Amortized cost		8,000
Unrealized gains		1,000
Fair value		9,000
Trading securities:
Fair value	34,000	37,000
Municipal bonds
Trading securities:
Fair value		501,000
Corporate bonds
Available for sale securities:
Amortized cost	3,018,000	14,568,000
Unrealized gains	6,000	61,000
Fair value	3,024,000	14,629,000
Trading securities:
Fair value	2,991,000	9,412,000
Common Stock
Trading securities:
Fair value	58,000	60,000
Affiliated mutual funds
Available for sale securities:
Amortized cost	116,723,000	87,710,000
Unrealized gains	6,498,000	5,899,000
Unrealized losses	(27,000)	(957,000)
Fair value	123,194,000	92,652,000
Trading securities:
Fair value	$ 88,051,000	$ 84,048,000