Share Incentive Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation information
Compensation Expense	$ 35,474	$ 24,832	$ 21,177
Compensation Capitalized	2,545	2,128	2,305
Compensation Equity	38,019	26,960	23,482
Dividends Incurred	1,487	1,183	1,320
Restricted shares [Member]
Compensation information
Compensation Expense	12,185	8,014	8,041
Compensation Capitalized	1,079	922	1,061
Compensation Equity	13,264	8,936	9,102
Dividends Incurred	967	949	1,121
Long Term Incentive Plan Units [Member]
Compensation information
Compensation Expense	13,108	5,004	3,344
Compensation Capitalized	501	303	297
Compensation Equity	13,609	5,307	3,641
Dividends Incurred	520	234	199
Employee Stock Option [Member]
Compensation information
Compensation Expense	9,569	10,970	8,711
Compensation Capitalized	945	782	834
Compensation Equity	10,514	11,752	9,545
Dividends Incurred	0	0	0
Employee Share Purchase Plan Discount [Member]
Compensation information
Compensation Expense	612	844	1,081
Compensation Capitalized	20	121	113
Compensation Equity	632	965	1,194
Dividends Incurred	$ 0	$ 0	$ 0