Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities Restricted Cash (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents, at Carrying Value	$ 438,961,000	$ 573,383,000	$ 515,646,000
Restricted Cash and Cash Equivalents	338,635,000	250,705,000	265,637,000
Cash and Cash Equivalents inclusive of Restricted Cash [Member]
Cash and Cash Equivalents, at Carrying Value	$ 777,596,000	$ 824,088,000	$ 781,283,000