Stock Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended					12 Months Ended									1 Months Ended	12 Months Ended			1 Months Ended
	Jul. 31, 2013	Jan. 31, 2013	Jul. 31, 2012	Jan. 31, 2012	Jul. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Jan. 31, 2014 Subsequent Event	Dec. 31, 2013 Restricted Stock Units Employees	Dec. 31, 2013 Restricted Stock Units Director	Dec. 31, 2013 Stock Options	May 21, 2013 Twenty Zero Six Incentive Compensation Plan	May 21, 2013 1996 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Employee Stock Purchase Plan to increase the number of shares issuable																			10,000,000	5,000,000
Aggregate number of shares issuable																			32,000,000	30,400,000
Period of stock granted to employees and executive officers vest in equal installments																4 years	1 year	4 years
Percentage of awards vesting on the first anniversary of grant date																	100.00%
Stock options term						7 years
Total unrecognized expense related to non-vested restricted stock unit awards and stock options						$ 51,300,000
Unrecognized expense related to non-vested restricted stock unit awards and stock options expected to be recognized over weighted average period, in years						2 years 4 months 24 days
Maximum percent of shares allowed to purchase						10.00%
Fair market value						$ 25,000
Maximum number of shares allowed to purchase						6,000
Percentage of common stock price paid						85.00%	85.00%	85.00%										100.00%
Common stock issued to employees	400,000	600,000	600,000	600,000	600,000										400,000
Value of common stock issued to employees per share									$ 14.98	$ 14.94	$ 11.91	$ 11.69	$ 11.59	$ 11.65