Summary of Significant Accounting Policies Supplemental Disclosures Related to Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental cash flow information
Total interest costs incurred	$ 53,487	$ 54,829	$ 58,455
Interest capitalized	1,551	7,569	5,490
Interest expense	51,936	47,260	52,965
Cash paid for interest, net of amounts capitalized	47,793	42,691	48,032
Cash paid for income taxes	641	633	404
Supplemental schedule of noncash investing and financing activities
Accounts payable and accrued liabilities for construction in progress	(435)	(14,733)	9,908
Accrued leasing commissions	(355)	(901)	763
Accrued placement fees for senior guaranteed notes payable	0	0	750
Reduction to capital for prepaid equity financing costs	$ 0	$ 54	$ 40