Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation costs	$ 7,210	$ 4,618	$ 21,536	$ 14,840
Less amount capitalized into qualifying real estate projects	(1,883)	(1,490)	(4,967)	(4,110)
Amount charged to operating expenses	5,327	3,128	16,569	10,730
Depreciation expense on capitalized stock-based compensation	227	139	679	586
Total stock-based compensation expense	5,554	3,267	17,248	11,316
Deferred income tax benefit	2,131	1,214	6,642	4,235
Stock option costs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation costs	320	698	985	2,677
Restricted stock costs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation costs	3,349	2,833	11,950	9,136
Performance share costs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation costs	$ 3,541	$ 1,087	$ 8,601	$ 3,027