Segment Reporting - Information about Segment Assets by Country (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	$ 3,384,209	$ 3,416,879
AEA [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	611,268	976,179
MEA [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	1,005,852	990,671
ASA [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	1,004,896	601,394
Corporate and Other [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Total assets	$ 762,193	$ 848,635