Stock Based Compensation - Summary of Weighted Average Grant-Date Fair Value of Common Stock Units and Share Awards Granted and Total Fair Value of Common Stock Units and Share Awards Vested (Detail) (Nonvested Common Stock Share Awards [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Nonvested Common Stock Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Shares	37	42	21
Weighted average grant-date fair value	$ 16.01	$ 16.15	$ 21.83
Fair value of vested	$ 669	$ 771	$ 407