Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Adjustment of Transactions Revenue (Detail)

v3.8.0.1
Summary of Significant Accounting Policies - Adjustment of Transactions Revenue (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Revenue Recognition [Abstract]                      
Gross service revenues                 $ 360,174 $ 493,678 $ 225,057
Total contractual adjustments and discounts                 (101,563) (249,595) (125,255)
Total Revenue $ 67,792 $ 63,052 $ 66,090 $ 61,676 $ 60,489 $ 60,761 $ 63,129 $ 59,704 $ 258,611 $ 244,083 $ 99,802