Gross Unrealized Gains and Losses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	$ 14,764	$ 23,030
Gross unrealized losses	6,254	854
Municipal
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	258	1,006
Gross unrealized losses	813	7
Corporate
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	9,955	19,141
Gross unrealized losses	3,228	486
Foreign
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	363	1,210
Gross unrealized losses	2,142	286
U.S. Government
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	924	1,395
Gross unrealized losses	60
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gains	3,264	278
Gross unrealized losses	$ 11	$ 75