Consolidated Balance Sheets (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	15,000,000us-gaap_PreferredStockSharesAuthorized	15,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, issued (in shares)	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Preferred stock, outstanding (in shares)	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Common Class A [Member]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	194,203,987	254,300,000
Common stock, issued (in shares)	17,176,046	128,759,772
Common stock, outstanding (in shares)	17,176,046	85,839,827
Common Class B [Member]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	87,008,602	87,008,602
Common stock, issued (in shares)	0	0
Common stock, outstanding (in shares)	0	0
No Class Common Stock [Member]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, issued (in shares)	369,987,783	352,204,571
Common stock, outstanding (in shares)	350,364,236	340,166,109

Face amount or stated value per share of common stock.

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