Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property and equipment - net of depreciation	$ 146,590	$ 128,430
Common stock, par value per share	$ 0.50	$ 0.50
Common stock, authorized shares	30,000,000	30,000,000
Common stock, issued shares	20,085,865	19,975,706
Common stock, outstanding shares	20,085,865	19,975,706
Centennial Founders, LLC [Member]
Property and equipment - net of depreciation	$ 72,115	$ 67,442