Notes and Bonds Payable (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Notes and bonds payable	$ 1,293,044	[1]	$ 1,393,537	[1]
Senior Notes [Member] | 5.125% Senior Notes Due 2014 [Member]
Debt Instrument [Line Items]
Senior notes face value	264,737		264,737
Unaccreted discount	(215)		(366)
Notes and bonds payable	$ 264,522		$ 264,371

[1] Level 3 - Fair value derived from valuation techniques in which one of more significant inputs or significant value drivers are unobservable.