Stock Based Compensation (Details Textual) (USD $)	9 Months Ended
	Sep. 30, 2012 Age	Mar. 06, 2012
Stock Based Compensation (Textual) [Abstract]
Purchase of shares of common stock at a weighted average price	$ 12.60
Due to significant growth the value of equity increased	$ 100,000,000
Due to significant growth the value of assets increased	2,000,000,000
Second vesting requirement for voting common stock	$ 18.90
Consecutive trading days of voting common stock trades	5 days
Change in control of outstanding stock	24.90%
Aggregate award of restricted stock units	57,031
Aggregated years from the date of issuance or upon a change in control	3 years
Allocation of restricted stock units to the annual deferral account	63,326
Participant vested in an Annual Deferral Accounts	100.00%
Involuntary termination	65
Unrecognized compensation expenses related to unvested restricted stock	5,800,000
Number of shares cancelled		160,884
Difference between latest sale price and exercise price of stock option	$ 14.00
Purchase of shares of common stock at a weighted-average price of per share	31,668
Unrecognized compensation expense related to unvested stock options	$ 2,300,000
Class B Non-Voting common stock [Member]
Stock Based Compensation (Textual) [Abstract]
Share Based Compensation Arrangement by Share Based Payment Award Partial Award Number of Restricted Stock Units Class B Non Voting Common Stock	211,640
Common stock [Member]
Stock Based Compensation (Textual) [Abstract]
Restricted stock units of shares received	169,313
Restricted stock units non-employee directors	15,876
2004 Plan [Member]
Stock Based Compensation (Textual) [Abstract]
Fully diluted tangible book value	50.00%
Number of shares of common stock issued stock option plan	2,500,000
2004 Plan [Member] | Class B Non-Voting common stock [Member]
Stock Based Compensation (Textual) [Abstract]
Share Based Compensation Arrangement by Share Based Payment Award Partial Award Number of Restricted Stock Units Class B Non Voting Common Stock	211,640
2004 Plan [Member] | Common stock [Member]
Stock Based Compensation (Textual) [Abstract]
Restricted stock units of shares	185,189
2010 Plan [Member]
Stock Based Compensation (Textual) [Abstract]
Fully diluted tangible book value	50.00%
Number of share of common stock issued	15.00%
Share Based Compensation Arrangement by Share Based Payment Award Upper Limit of Maximum Number of Shares of Common Stock Available	3,333,334