Stock Compensation - Summary of Stock Options Outstanding and Related Activity (Detail) - HGI [Member] - $ / shares shares in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Warrant [Member]
Options (in shares):
Stock options outstanding at September 30, 2015	1,800	1,800
Stock options outstanding at March 31, 2016		1,800		1,800
Stock options vested and exercisable at March 31, 2016		600
Weighted Average Exercise Price (in dollars per share):
Granted		$ 13.13		$ 13.13
Stock options vested and exercisable at March 31, 2016	$ 13.13
Weighted Average Grant Date Fair Value (in dollars per share):
Granted		3.22		$ 3.22
Stock options vested and exercisable at March 31, 2016		$ 3.22
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		1,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price		$ 13.13
Restricted award expected to vest		$ 3.22
Employee Stock Option [Member]
Options (in shares):
Stock options outstanding at September 30, 2015	4,770	4,770
Granted		28	822
Exercised		(401)
Stock options outstanding at March 31, 2016		4,397		4,770
Stock options vested and exercisable at March 31, 2016		3,347
Weighted Average Exercise Price (in dollars per share):
Granted		$ 13.93
Exercised		8.07
Stock options outstanding at March 31, 2016		9.39		$ 9.25
Stock options vested and exercisable at March 31, 2016		8.40
Weighted Average Grant Date Fair Value (in dollars per share):
Granted		5.07
Exercised		3.12
Stock options outstanding at March 31, 2016		3.77		$ 3.70
Stock options vested and exercisable at March 31, 2016		$ 3.37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number		4,397
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price		$ 9.39
Restricted award expected to vest		$ 3.77