Significant Accounting Policies (Schedule, Cash, Cash Equivalent, Restricted Cash) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Cash and cash equivalents	$ 118,799	$ 57,686	$ 108,787
Restricted cash	131,442	111,282	77,198	$ 26,400
Cash, cash equivalents and restricted cash	$ 250,241	$ 168,968	$ 185,985	$ 175,419