Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Address, City or Town Entity Address, City or Town Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One Security Exchange Name Security Exchange Name Document Information [Line Items] Document Information [Line Items] City Area Code City Area Code Cover page. Cover [Abstract] Entity Central Index Key Entity Central Index Key Entity Tax Identification Number Entity Tax Identification Number Entity File Number Entity File Number Document Type Document Type Document Information [Table] Document Information [Table] Entity Emerging Growth Company Entity Emerging Growth Company Title of 12(b) Security Title of 12(b) Security Amendment Flag Amendment Flag Entity Address, State or Province Entity Address, State or Province Trading Symbol Trading Symbol Document Period End Date Document Period End Date Entity Registrant Name Entity Registrant Name Written Communications Written Communications Pre-commencement Tender Offer Pre-commencement Tender Offer Common Stock, par value $0.01 per share Common Stock [Member] Class of Stock [Axis] Class of Stock [Axis] 2.250% Senior Notes due 2023 Senior Notes Due Two Thousand And Twenty Three [Member] Senior Notes Due Two Thousand And Twenty Three [Member] Local Phone Number Local Phone Number Entity Address, Postal Zip Code Entity Address, Postal Zip Code Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Class of Stock [Domain] Class of Stock [Domain]