Share Based Compensation (Summary of Future Compensation Expense in Connection With Vesting of Existing Time Based Restricted Share Awards) (Detail) - Restricted Stock [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 8,364
Year One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	3,949
Year Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	2,827
Year Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	1,431
2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 157