Inome Taxes (Income Tax Provision) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Current:
Federal									$ (395)	$ (7)	$ 97
State									256	588	551
Foreign									185	112	71
Total current income tax provision									46	693	719
Deferred:
Federal									59,837	1,506	95
State									6,664	(1,095)	(854)
Foreign									(253)	(1,230)	(807)
Total deferred tax (benefit) provision									66,248	(819)	(1,566)
Income tax (benefit) provision	$ 142	$ 70,842	$ (3,453)	$ (1,236)	$ (178)	$ 30	$ (15)	$ 37	$ 66,294	$ (126)	$ (847)