Share Based Compensation - Summarized Activity of Cash-Settled Stock Appreciation Rights (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards settled in cash	$ 206	$ 1,181	$ 3,458
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms	4 years	4 years
Balance at beginning of year	458
Granted, Rights Outstanding	90
Exercised, Rights Outstanding	(39)
Forfeited, Rights Outstanding	(22)
Balance at end of period	487	458
Exercisable at end of period, Rights Outstanding	414
Non-vested at beginning of year, Weighted Average Grant Date Fair Value	$ 12.54
Granted, Weighted Average Exercise Price	14.08
Exercised, Weighted Average Exercise Price	9.29
Forfeited, Weighted Average Grant Date Fair Value	15.00
Non-vested at end of period, Weighted Average Grant Date Fair Value	12.97	$ 12.54
Exercisable at end of period, Weighted Average Exercise Price	$ 12.77
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Exercisable Weighted Average Remaining Contractual Term	3 years
Aggregate Intrinsic Value	$ 404	$ 1,732
Exercisable at end of period, Aggregate Intrinsic Value	404
Cash Settled Restricted Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards settled in cash	$ 2,469	$ 2,286	$ 3,780
Balance at beginning of year	185
Granted, Rights Outstanding	60
Forfeited, Rights Outstanding	(11)
Balance at end of period	117	185
Non-vested at beginning of year, Weighted Average Grant Date Fair Value	$ 18.49
Forfeited, Weighted Average Grant Date Fair Value	18.83
Non-vested at end of period, Weighted Average Grant Date Fair Value	$ 16.00	$ 18.49