Stock Repurchase Program (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended	12 Months Ended			45 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares repurchased as part of stock repurchase programs	4,400,000	15,812,566	7,185,257	1,150,000	28,547,823
Cost of shares repurchased	$ 171,627	$ 436,419	$ 125,341	$ 19,138	$ 752,525