Restatement and Revision of Previously Issued Unaudited Financial Statements - Effect of Revisions on affected Line Items on Condensed Consolidated Statement of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Net income (loss)	$ (17,271)	$ 60,645	$ 78,325
Provision for doubtful accounts	15,305	10,654
Deferred income taxes	(15,384)	(4,224)
Restricted cash	(1,512)	(357)
Accounts receivable	(42,685)	(17,521)
Other operating assets and liabilities	(5,910)	23,636
Net cash flows from operating activities	(43,915)	35,984
As Previously Reported [Member]
Net income (loss)	31,130	61,071
Provision for doubtful accounts	19,885	15,601
Deferred income taxes	13,211	(3,742)
Restricted cash	(118)	1,005
Accounts receivable	(46,649)	(21,906)
Other operating assets and liabilities	(10,693)	22,166
Net cash flows from operating activities	(43,418)	37,346
Revisions [Member]
Net income (loss)		(426)
Provision for doubtful accounts		(4,947)
Deferred income taxes		(482)
Restricted cash		(1,362)
Accounts receivable		4,385
Other operating assets and liabilities		1,470
Net cash flows from operating activities		(1,362)
As Revised [Member]
Net income (loss)		60,645
Provision for doubtful accounts		10,654
Deferred income taxes		(4,224)
Restricted cash		(357)
Accounts receivable		(17,521)
Other operating assets and liabilities		23,636
Net cash flows from operating activities		$ 35,984