Summary of Restatement on Affected Line Items in Condensed Consolidated Statement of Shareholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Condensed Consolidated Statement of Shareholders' Equity Data
Net income	$ 10,447	$ 759	$ 22,561
Balance as of March 31, 2015	147,923	116,243	142,072	$ 115,646
Retained Earnings [Member]
Condensed Consolidated Statement of Shareholders' Equity Data
Net income	10,447	759	22,561
Balance as of March 31, 2015	974,184	$ 941,176	$ 963,737	$ 940,449
As Previously Reported [Member]
Condensed Consolidated Statement of Shareholders' Equity Data
Balance as of March 31, 2015	153,856
As Previously Reported [Member] | Retained Earnings [Member]
Condensed Consolidated Statement of Shareholders' Equity Data
Net income	10,447
Balance as of March 31, 2015	980,117
Interest Method Adjustment [Member]
Condensed Consolidated Statement of Shareholders' Equity Data
Balance as of March 31, 2015	(5,933)
Interest Method Adjustment [Member] | Retained Earnings [Member]
Condensed Consolidated Statement of Shareholders' Equity Data
Net income	0
Balance as of March 31, 2015	$ (5,933)