Organization, Basis of Presentation and Recent Accounting Pronouncements (Recent Accounting Pronouncements) (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncement, Early Adoption [Line Items]
Net Cash Provided by Operating Activities	$ 91,901	$ 60,882
Net Decrease in Cash and Cash Equivalents and Restricted Cash	(13,474)	(209,732)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 657,342	565,220	$ 670,816	$ 774,952
As previously reported [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in Restricted Cash		(13,888)
Net Cash Provided by Operating Activities		46,994
Net Decrease in Cash and Cash Equivalents and Restricted Cash		(223,620)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		530,587		754,207
Adjustment [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in Restricted Cash		13,888
Net Cash Provided by Operating Activities		13,888
Net Decrease in Cash and Cash Equivalents and Restricted Cash		13,888
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		34,633		20,745
As Adopted [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in Restricted Cash		0
Net Cash Provided by Operating Activities		60,882
Net Decrease in Cash and Cash Equivalents and Restricted Cash		(209,732)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		$ 565,220		$ 774,952