Organization, Basis of Presentation and Recent Accounting Pronouncements (Recent Accounting Pronouncements) (Details 1) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncement, Early Adoption [Line Items]
Net Cash Provided by Operating Activities	$ 131,568	$ 146,601
Net Decrease in Cash and Cash Equivalents and Restricted Cash	(215,670)	(142,734)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 455,146	632,218	$ 670,816	$ 774,952
As previously reported [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Increase in Restricted Cash		(11,133)
Net Cash Provided by Operating Activities		135,468
Net Decrease in Cash and Cash Equivalents and Restricted Cash		(153,867)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		600,340		754,207
Adjustment [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Increase in Restricted Cash		11,133
Net Cash Provided by Operating Activities		11,133
Net Decrease in Cash and Cash Equivalents and Restricted Cash		11,133
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		31,878		20,745
As Adopted [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Increase in Restricted Cash		0
Net Cash Provided by Operating Activities		146,601
Net Decrease in Cash and Cash Equivalents and Restricted Cash		(142,734)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		$ 632,218		$ 774,952