Employee Benefits and Incentive Plans - Summary of Percentage of Target Award to Vest (Detail) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2016
Below the 30th Percentile [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Percentage of Shares Vested	0.00%
At the Thirty Percentile [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Percentage of Shares Vested	50.00%
At the Fifty Five Percentile [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Percentage of Shares Vested	100.00%
At or Above the Eighty Percentile [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Percentage of Shares Vested	175.00%