Accumulated Other Comprehensive Income (Loss) (Other Comprehensive Income (Loss) Reclassification Adjustments) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income Loss [Line Items]
Pretax change before reclassifications	$ 8,976	$ (31,030)	$ 99,678	$ (59,176)
Reclassifications out of AOCI	(2,855)	6,464	4,298	23,019
Tax effect	(3,399)	2,266	(38,004)	833
Total other comprehensive income (loss), net of tax	2,722	(22,300)	65,972	(35,324)
Unrealized Gains (Losses) on Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Pretax change before reclassifications	12,435	(15,614)	96,612	(29,966)
Reclassifications out of AOCI	(8,687)	(108)	(13,222)	1,545
Tax effect	(1,169)	4,780	(31,303)	9,047
Total other comprehensive income (loss), net of tax	2,579	(10,942)	52,087	(19,374)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Pretax change before reclassifications	(3,459)	(15,416)	3,066	(29,210)
Total other comprehensive income (loss), net of tax	(3,459)	(15,416)	3,066	(29,210)
Pension Benefit Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Reclassifications out of AOCI	5,832	6,572	17,520	21,474
Tax effect	(2,230)	(2,514)	(6,701)	(8,214)
Total other comprehensive income (loss), net of tax	$ 3,602	$ 4,058	$ 10,819	$ 13,260