Equity-Based Compensation - Shares of Time-Vested Restricted Stock Granted and Vesting Schedules of Restricted Stock Awards (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	355,309
At Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	130,123
After Three Years Of Service [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	225,186
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	167,515	169,081	152,636
Restricted Stock Awards [Member] | At Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	18,095
Restricted Stock Awards [Member] | After Three Years Of Service [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	149,420
Performance Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	187,794	72,470	62,874
Performance Share Awards [Member] | At Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	112,028
Performance Share Awards [Member] | After Three Years Of Service [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	75,766