Long-Term Stock Incentive Plans - Narrative (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Long-Term Stock Incentive Plans:
Weighted average remaining contractual term of stock options outstanding, years	4 years 3 months 18 days	5 years 6 months
Weighted average remaining contractual term of stock options exercisable, years	4 years	4 years 9 months 18 days
Total unrecognized compensation cost related to nonvested share-based compensation awards	$ 679,000.0	$ 4,200,000
Total unrecognized compensation cost related to nonvested share-based compensation awards weighted average recognition period, years	3 months	1 year 1 month 6 days
Stock Options [Member]
Long-Term Stock Incentive Plans:
Long-term stock compensation - vesting period	4 years
Long-term stock compensation - vesting installments	4 years
Long-term stock compensation - minimum contractual term	5 years
Long-term stock compensation - maximum contractual term	10 years
Equity Incentive Plan 2010 [Member]
Long-Term Stock Incentive Plans:
Long-term stock compensation - ceiling shares	25,000,000
The Prior Plan [Member] | Minimum [Member]
Long-Term Stock Incentive Plans:
Long-term stock compensation - ceiling shares	500,000
Long-term stock compensation - granting of options authorized, percent of diluted outstanding common stock	9.50%
The Prior Plan [Member] | Maximum [Member]
Long-Term Stock Incentive Plans:
Long-term stock compensation - ceiling shares	8,932,921