Fair Value Disclosures, Carrying and Fair Values of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
4.50% Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Stated interest rate (in hundredths)	4.50%	4.50%
7.50% Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Stated interest rate (in hundredths)	7.50%	7.50%
7.50% Senior Exchange Convertible Notes Member [Member]
Notes, mortgage notes and other debt [Abstract]
Stated interest rate (in hundredths)	7.50%	7.50%
Carrying Amount [Member] | 4.50% Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Notes	5,402	5,402
Carrying Amount [Member] | 7.50% Notes and 7.50% Senior Exchange Convertible Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Notes	100,000	100,000
Fair Value [Member] | 4.50% Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Notes	5,336	5,343
Fair Value [Member] | 7.50% Notes and 7.50% Senior Exchange Convertible Notes [Member]
Notes, mortgage notes and other debt [Abstract]
Notes	101,790	101,500