XML 80 R91.htm IDEA: XBRL DOCUMENT

Fair Value of Financial Instruments - Changes in the Level 3 Fair Value Category of Unobservable Inputs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 324,509us-gaap_AvailableForSaleSecurities
Purchases		103,320	134,435
Sales	57,928	91,039	60,513
Ending Balance	248,492us-gaap_AvailableForSaleSecurities	324,509us-gaap_AvailableForSaleSecurities
State and Local Governments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Ending Balance	74,303	81,473
Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Ending Balance	7,931	10,346
Level 3 [Member] \| State and Local Governments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	10,346	16,408
Change in Market Value	(1,355)	(1,853)
Purchases		519
Sales	0	0
Payments & Maturities	(1,060)	(4,728)
Ending Balance	7,931	10,346
Level 3 [Member] \| State and Local Governments [Member] \| Tax - Exempt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	8,802	14,863
Change in Market Value	(1,104)	(1,852)
Purchases		519
Sales	0	0
Payments & Maturities	(1,060)	(4,728)
Ending Balance	6,638	8,802
Level 3 [Member] \| State and Local Governments [Member] \| Taxable [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	1,544	1,545
Change in Market Value	(251)	(1)
Purchases
Sales	0	0
Payments & Maturities
Ending Balance	$ 1,293	$ 1,544