Goodwill and Other Intangible Assets - Schedule of Activity in Goodwill and Intangible Assets, Net (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, net, beginning of period	$ 44,633	$ 48,711	$ 52,096
Acquisition	1,075	356	560
Amortization expense	(3,925)	(4,434)	(3,945)
Intangible assets, net, end of period	41,783	44,633	48,711
Goodwill	5,260	5,260	4,795
Acquisition	0		465
Goodwill	$ 5,260	$ 5,260	$ 5,260