Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	12,000	12,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
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	32,379,908	32,254,199
Common stock, shares outstanding	22,015,738	21,890,029
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