Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	12,000us-gaap_PreferredStockSharesAuthorized	12,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Class A [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	32,745,151	32,254,199
Common stock, shares outstanding	21,806,632	21,741,586
Class B [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	1,495,490	1,495,490
Common stock, shares outstanding	1,495,490	1,495,490

Face amount or stated value per share of common stock.

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