Capital Stock and Dividend Restrictions (Details) (USD $)	2 Months Ended	12 Months Ended							1 Months Ended	12 Months Ended
	Mar. 05, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Series A Preferred Stock	Dec. 31, 2010 Class B Common Stock votes_per_shares	Dec. 31, 2012 Class B Common Stock	Dec. 31, 2011 Class B Common Stock	Mar. 31, 2010 Class A Common Stock	Dec. 31, 2010 Class A Common Stock vote	Dec. 31, 2012 Class A Common Stock	Dec. 31, 2011 Class A Common Stock	Mar. 30, 2010 Class A Common Stock	Mar. 29, 2010 Class A Common Stock	Mar. 05, 2010 Class A Common Stock	Mar. 04, 2010 Class A Common Stock
Preferred Stock
Nonvoting, noncumulative preferred stock, shares outstanding		5,000	5,000		5,000,000
Preferred stock, dividend rate, percentage					6.75%
Preferred stock, value, issued					$ 50,000,000
Preferred stock, dividend rate, per-dollar-amount					$ 675
Preferred stock, redemption price per share					$ 10,000
Preferred stock, aggregate redemption price					50,150
Common Stock, Recapitalization
Recapitalization, common stock votes per share						5
Stock issued during period, shares, stock split	4					4
Common stock, shares authorized															100,000,000	20,000,000
Common stock, vote per share										1
Common Stock
Common stock, shares issued, IPO														10,000,000
Common stock, additional shares issued from IPO													1,500,000
Proceeds from issuance of common stock		$ 1,911,000	$ 385,000	$ 167,400,000					$ 153,153,000
Common stock, shares, outstanding							25,654,954	26,540,745			17,635,369	16,443,429