Stock-Based Compensation Plans (Narrative) (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of common shares available for grant		10,900,000
Common shares available for future grants		2,300,000
Holding period before vesting		1 year
Maximum contractual life		10 years 0 months
Number of options outstanding		2,325,797	2,476,645
Intrinsic value of options exercised		$ 1,800,000	$ 777,100	$ 102,400
Weighted-average remaining contractual term of options expected to vest, in years		8 years 8 months
Aggregate intrinsic value of options outstanding		19,900,000
Aggregate intrinsic value of options exercisable		15,300,000
Aggregate intrinsic value of options, vested and expected to vest		4,300,000
Fair value		2,000,000	9,100,000	4,800,000
Compensation expense		10,664,000	8,955,000	6,040,000
Liabilities		34,000	27,000
Share Based Compensation Arrangements by Share Based Payment Award Equity Instruments Other Than Options Modified In Period	164,260
Individual Counterparty [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock shares granted during period		100,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense		3,902,000	2,405,000	809,000
Non-Vested Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		2,000,000
Weighted-average vesting period		1 year 8 months
Non-Qualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding		2,129,892
Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding		195,905.000
Time Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock shares granted during period		246,133
Performance Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years 0 months
Restricted stock shares granted during period		163,519
Vesting range, minimum		0.00%
Vesting range, maximum		200.00%
Vesting percentage		50.00%
Non-Vested Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		9,500,000
Weighted-average vesting period		1 year 11 months
Long Term Cash Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of days prior to the grant date		0 years 0 months 10 days
Compensation expense		$ 8,000	$ 1,200,000	$ 3,000,000
Minimum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years 0 months
Minimum [Member] | Time Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year 0 months
Minimum [Member] | Long Term Cash Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years 0 months
Maximum [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years 0 months
Maximum [Member] | Time Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years 0 months
Maximum [Member] | Long Term Cash Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years 0 months