Revenue Recognition and Contractual Adjustments - Adjustment of Transactions Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Revenue Recognition [Abstract]
Gross service revenues	$ 83,938	$ 132,720
Total contractual adjustments and discounts	(22,262)	(73,016)
Total Revenue	$ 61,676	$ 59,704

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueServicesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration