Income Taxes- Reconciliation of Statutory Federal Income Tax Rate to Effective Income Tax Rate (Detail)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Federal rate (percent)	35.00%	35.00%
State and local income taxes, net of federal income tax benefit (percent)	3.00%	2.30%
Tax-exempt income (percent)	(2.80%)	(3.60%)
Foreign operations (percent)	(4.50%)	(5.10%)
Tax credits (percent)	(3.40%)	(5.00%)
Tax litigation (percent)	19.80%	0.00%
Other – net (percent)	(1.60%)	(0.30%)
Effective rate (percent)	45.50%	23.30%