Investments in Unconsolidated Entities and Joint Ventures - Information for Significant Unconsolidated Equity Method Investees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
WTLPG
Schedule of Equity Method Investments [Line Items]
Total Assets	$ 812,464	$ 819,342	$ 827,697
Long-Term Debt	0	0	0
Members’ Equity/Partners' Capital	790,406	804,023	818,546
Revenues	88,468	100,708	95,315
Net Income	$ 23,883	$ 46,294	38,698
Cardinal
Schedule of Equity Method Investments [Line Items]
Total Assets			0
Long-Term Debt			0
Members’ Equity/Partners' Capital			0
Revenues			46,488
Net Income			$ 1,911