Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 262,594	$ 262,813
Other	(218)	(219)
Goodwill, Ending Balance	262,376	262,594
Hub [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	233,205	233,424
Other	(218)	(219)
Goodwill, Ending Balance	232,987	233,205
Mode [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	29,389	29,389
Other	0	0
Goodwill, Ending Balance	$ 29,389	$ 29,389