Summary of Restricted Stock Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Number of shares
Number of shares, Unvested, beginning of year	1,802	2,298	2,738
Number of shares, Granted	717	744	795
Number of shares, Vested	(871)	(1,132)	(1,087)
Number of shares, Forfeited	(78)	(108)	(148)
Number of shares, Unvested, end of year	1,570	1,802	2,298
Weighted average grant date fair value, Unvested
Weighted average grant date fair value, Unvested, beginning of year	$ 7.02	$ 5.49	$ 4.43
Weighted average grant date fair value, Granted	$ 9.85	$ 9.21	$ 8.65
Weighted average grant date fair value, Vested	$ 5.67	$ 5.42	$ 5.22
Weighted average grant date fair value, Forfeited	$ 8.66	$ 6.22	$ 4.89
Weighted average grant date fair value, Unvested, end of year	$ 8.98	$ 7.02	$ 5.49