Significant Accounting Policies - Additional Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Accounting Policies [Abstract]
Cash paid for interest	$ 10,519	$ 17,681
Cash paid for income taxes	45,186	42,944
Unsettled security transactions	61,974	36,301
Loans foreclosed and transferred to other real estate owned and foreclosed assets	1,993	3,251
Other real estate, disposals	1,799	0
Loans to facilitate the sale of other real estate owned	102	228
Deferred gain on sale of building and parking garage	$ 0	$ 922