Share Based Compensation - Summary of Expense Related to Share-Based Payments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized	$ 26,676	$ 19,275	$ 21,743
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized	11,677	10,341	9,654
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized	$ 14,999	$ 8,934	$ 12,089