Segment Information, Nature of Operations, and Certain Concentrations - Interest Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated interest income	$ 7,696	$ 6,251	$ 7,302
Mortgage Banking [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Interest income	6,485	4,940	4,983
Operating Segments [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Interest income	6,485	4,940	4,983
Consolidation adjustments and other [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Other unallocated interest income	$ 1,211	$ 1,311	$ 2,319