Components of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Other Intangible Assets [Line Items]
Intangible Assets, Gross Amount	$ 20,543	$ 20,543
Finite-lived intangible assets, Accumulated Amortization	(8,699)	(7,404)
Intangible Assets, Net Carrying Value	11,844	13,139
Hub [Member] | Customer Relationships [Member]
Other Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	5,181	5,181
Finite-lived intangible assets, Accumulated Amortization	(3,792)	(3,350)
Finite-lived intangible assets, Net Carrying Value	$ 1,389	$ 1,831
Hub [Member] | Customer Relationships [Member] | Minimum [Member]
Other Intangible Assets [Line Items]
Intangible assets estimated useful life	7 years	7 years
Hub [Member] | Customer Relationships [Member] | Maximum [Member]
Other Intangible Assets [Line Items]
Intangible assets estimated useful life	15 years	15 years
Mode [Member] | Agency/Customer Relationships [Member]
Other Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	$ 15,362	$ 15,362
Finite-lived intangible assets, Accumulated Amortization	(4,907)	(4,054)
Finite-lived intangible assets, Net Carrying Value	$ 10,455	$ 11,308
Intangible assets estimated useful life	18 years	18 years