Share and Incentive-Based Compensation - Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	$ 6,606	$ 7,222	$ 22,660	$ 11,050
Performance units compensation expense	1,289	972	4,794	1,562
Total share and incentive-based compensation expense	7,895	8,194	27,454	12,612
Less: Capitalized compensation expense	(679)	(967)	(889)	(1,629)
Share and incentive-based compensation expense, net	7,216	7,227	26,565	10,983
Recurring Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	634	5,397	3,738	9,225
Performance units compensation expense	227	972	776	1,562
Total share and incentive-based compensation expense	861	6,369	4,514	10,787
Less: Capitalized compensation expense	(124)	(967)	(334)	(1,629)
Share and incentive-based compensation expense, net	737	5,402	4,180	9,158
Executive Terminations
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	82	1,825	9,196	1,825
Performance units compensation expense	(216)	0	2,151	0
Total share and incentive-based compensation expense	(134)	1,825	11,347	1,825
Less: Capitalized compensation expense	0	0	0	0
Share and incentive-based compensation expense, net	(134)	1,825	11,347	1,825
Reduction In Force
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	99	0	3,935	0
Performance units compensation expense	(31)	0	558	0
Total share and incentive-based compensation expense	68	0	4,493	0
Less: Capitalized compensation expense	0	0	0	0
Share and incentive-based compensation expense, net	68	0	4,493	0
Change In Control
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	5,791	0	5,791	0
Performance units compensation expense	1,309	0	1,309	0
Total share and incentive-based compensation expense	7,100	0	7,100	0
Less: Capitalized compensation expense	(555)	0	(555)	0
Share and incentive-based compensation expense, net	6,545	0	6,545	0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	5,876	6,811	20,477	10,440
Restricted Stock | Recurring Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	603	4,986	3,379	8,615
Restricted Stock | Executive Terminations
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	0	1,825	8,140	1,825
Restricted Stock | Reduction In Force
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	92	0	3,777	0
Restricted Stock | Change In Control
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	5,181	0	5,181	0
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	730	411	2,183	610
Performance Share Units | Recurring Compensation Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	31	411	359	610
Performance Share Units | Executive Terminations
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	82	0	1,056	0
Performance Share Units | Reduction In Force
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	7	0	158	0
Performance Share Units | Change In Control
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost
Equity-classified awards compensation expense	$ 610	$ 0	$ 610	$ 0