Shareholders' Equity - Non-employee Equity Awards, Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of year, Number	3,423,566
Granted, Number	390,871
Exercised, Number	(887,829)
Forfeited or expired, Number	(269,220)
Outstanding at end of year, Number	2,657,388
Exercisable at end of year, Number	1,503,242
Outstanding at beginning of year, Weighted average exercise price	$ 10.36
Granted, Weighted average exercise price	$ 15.55
Exercised, Weighted average exercise price	$ 9.32
Forfeited or expired, Weighted average exercise price	$ 18.79
Outstanding at end of year, Weighted average exercise price	$ 10.62
Exercisable at end of year, Weighted average exercise price	$ 9.50
Outstanding at end of year, Weighted average remaining contractual term	3 years 9 months 15 days
Exercisable at end of year, Weighted average remaining contractual term	2 years 2 months 27 days
Outstanding at end of year, Aggregate intrinsic value	$ 11,500
Exercisable at end of year, Aggregate intrinsic value	8,061
Non Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of year, Number	64,475
Granted, Number	6,705
Exercised, Number	(7,075)
Forfeited or expired, Number	(9,025)
Outstanding at end of year, Number	55,080
Exercisable at end of year, Number	36,377
Outstanding at beginning of year, Weighted average exercise price	$ 12.00
Granted, Weighted average exercise price	$ 15.57
Exercised, Weighted average exercise price	$ 11.31
Forfeited or expired, Weighted average exercise price	$ 20.17
Outstanding at end of year, Weighted average exercise price	$ 11.18
Exercisable at end of year, Weighted average exercise price	$ 10.61
Outstanding at end of year, Weighted average remaining contractual term	3 years 5 months 1 day
Exercisable at end of year, Weighted average remaining contractual term	2 years 4 months 17 days
Outstanding at end of year, Aggregate intrinsic value	205
Exercisable at end of year, Aggregate intrinsic value	$ 153