Entity Central Index Key Entity Central Index Key Entity Address, Address Line One Entity Address, Address Line One Trading Symbol Trading Symbol Entity File Number Entity File Number Common Class B [Member] Common Class B [Member] Soliciting Material Soliciting Material Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Address, Postal Zip Code Entity Address, Postal Zip Code Class of Stock [Domain] Class of Stock [Domain] City Area Code City Area Code Document Information [Line Items] Document Information [Line Items] Title of 12(b) Security Title of 12(b) Security Amendment Flag Amendment Flag Security Exchange Name Security Exchange Name Entity Registrant Name Entity Registrant Name Document Period End Date Document Period End Date Entity Tax Identification Number Entity Tax Identification Number Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Convertible Preferred Stock Convertible Preferred Stock [Member] Entity Address, City or Town Entity Address, City or Town Class of Stock [Axis] Class of Stock [Axis] Local Phone Number Local Phone Number Common Class A [Member] Common Class A [Member] Written Communications Written Communications Cover [Abstract] Cover [Abstract] Document Type Document Type Document Information [Table] Document Information [Table] Entity Emerging Growth Company Entity Emerging Growth Company Entity Address, State or Province Entity Address, State or Province Pre-commencement Tender Offer Pre-commencement Tender Offer