Other Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Component Of Operating Cost And Expense [Line Items]
Other expenses	$ 0	$ 502	$ 0	$ 1,409
Software Systems [Member]
Component Of Operating Cost And Expense [Line Items]
Other expenses		$ 502		659
Natural Disasters and Other Casualty Events [Member]
Component Of Operating Cost And Expense [Line Items]
Other expenses				$ 750