Non-Vested Share Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Non-vested shares outstanding beginning	477,000
Shares, Granted	216,000
Shares, Vested	(234,000)
Shares, Cancelled	0
Shares, Non-vested shares outstanding ending	459,000
Shares, Non-vested shares vested or expected to vest	429,000
Weighted Average Grant Date Fair Value, Non-vested shares outstanding beginning	$ 9.66
Weighted Average Grant Date Fair Value, Granted	$ 12.82
Weighted Average Grant Date Fair Value, Vested	$ 10.12
Weighted Average Grant Date Fair Value, Cancelled	$ 0
Weighted Average Grant Date Fair Value, Non-vested shares outstanding ending	$ 10.91
Weighted Average Grant Date Fair Value, Non-vested shares vested or expected to vest	$ 10.91
Aggregate Intrinsic Value, Non-vested shares outstanding ending	$ 5,715
Aggregate Intrinsic Value, Non-vested shares vested or expected to vest	$ 5,341