Significant Accounting Policies - Estimated Useful Lives of Depreciable Property (Detail)	12 Months Ended
	Dec. 31, 2015
Building and Improvements [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciable property estimated useful lives	40 years
Minimum [Member] | Office Equipment and Furniture [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciable property estimated useful lives	4 years
Minimum [Member] | Computer Software [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciable property estimated useful lives	3 years
Maximum [Member] | Office Equipment and Furniture [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciable property estimated useful lives	7 years
Maximum [Member] | Computer Software [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciable property estimated useful lives	15 years