Number of new stock issued during the period.

+ References+ Details

Face amount or stated value per share of stock classified as temporary equity; generally not indicative of the fair market value per share. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References+ Details

Earnings Per Share Offerings (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended				12 Months Ended					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 19, 2012	Dec. 31, 2012 Class A [Member]	Dec. 31, 2012 Tangible Equity Units [Member]	Sep. 19, 2012 Tangible Equity Units [Member]	Oct. 02, 2015 Tangible Equity Units [Member] Minimum [Member]	Oct. 02, 2015 Tangible Equity Units [Member] Maximum [Member]	Dec. 31, 2012 TEUs - Amortizing Notes [Member]
Tangible Equity Units Number Of Shares Upon Conversion Per Unit								1.2355	1.5444
Stock issued	3,791,004				3,791,004	2,300,000
Coupon rate										5.00%
Stock issued during period, per share fair value				$ 64.75
Shares issued as a result of the underwriter's exercise of their over-allotment option					525,000	300,000
Net proceeds from Class A common stock issuance	$ 234,340	$ 0	$ 0
Stated amount per share							$ 100.00
Net proceeds from TEU issuance		$ 0	$ 0			$ 222,856
Weighted average shares impact resulting from offerings during the period					1,066,867	850,773