Unvested RSAs by Grant-Date Fair Value (Detail) (Restricted Stock Award [Member]) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSAs at Year End	6,710	6,379	4,764	5,158
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Weighted Average Remaining Contractual Terms	1 year 4 months 24 days
$10.01-$20.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSAs at Year End	62
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Weighted Average Remaining Contractual Terms	1 year 8 months 12 days
$20.01-$30.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSAs at Year End	3,363
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Weighted Average Remaining Contractual Terms	1 year 1 month 6 days
$30.01-$40.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSAs at Year End	3,285
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Outstanding Weighted Average Remaining Contractual Terms	1 year 9 months 18 days