Pre-Tax Book Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pre-tax Income [Line Items]
Income before income taxes	$ 229,166	$ 200,662	$ 182,472
Domestic
Pre-tax Income [Line Items]
Income before income taxes	152,790	149,988	178,451
Foreign
Pre-tax Income [Line Items]
Income before income taxes	$ 76,376	$ 50,674	$ 4,021