Quarterly report pursuant to Section 13 or 15(d)

Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details)

v3.10.0.1
Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Cash, Cash Equivalents and Restricted Cash [Line Items]            
Cash and cash equivalents $ 120,357 $ 101,736 $ 138,285 $ 99,565 $ 106,514 $ 112,183
Total cash, cash equivalents, and restricted cash reported in the statements of cash flows 124,737 105,280 143,775 102,608 107,532 114,410
Prepaid Expenses and Other Current Assets            
Cash, Cash Equivalents and Restricted Cash [Line Items]            
Restricted cash and cash equivalents 2,926 3,160 5,106 2,627 591 1,709
Other Assets            
Cash, Cash Equivalents and Restricted Cash [Line Items]            
Restricted cash and cash equivalents $ 1,454 $ 384 $ 384 $ 416 $ 427 $ 518