Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2002
Deferred tax assets:
Allowance for loan losses	$ 48,042	$ 53,407
Depreciation	13,327	4,972
Deferred compensation		5,075
Employee benefits	14,325	11,775
Investment securities, including other-than-temporary impairment losses	24,735	24,196
Net operating loss carryforwards	53,926	62,053
Purchase accounting	6,863	14,251
Accrued interest		12,515
Other	21,063	23,416
Total deferred tax assets	182,281	211,660
Deferred tax liabilities:
Pension plans	21,774
Other investments	11,096	11,182
Deferred income		15,886
Other	17,811	13,353
Total deferred tax liabilities	50,681	40,421
Net deferred tax asset (included in other assets)	$ 131,600	$ 171,239