Annual report pursuant to Section 13 and 15(d)

Supplemental Disclosures to Consolidated Statements of Cash Flows (Cash, Cash Equivalents and Restricted Cash) (Details)

v3.10.0.1
Supplemental Disclosures to Consolidated Statements of Cash Flows (Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]        
Cash and cash equivalents $ 491,257 $ 573,210 $ 487,163  
Restricted cash included in other current assets 775 938 964  
Total cash and cash equivalents and restricted cash at end of period $ 492,032 $ 574,148 $ 488,127 $ 2,001,481