Segment Information, Nature of Operations, and Certain Concentrations - Depreciation and Amortization (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	$ 17,614	$ 13,391	$ 8,100
Operating Segments [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	13,713	9,225	7,195
Operating Segments [Member] | Homebuilding Mid Atlantic [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	6,489	4,784	3,886
Operating Segments [Member] | Homebuilding North East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,208	853	631
Operating Segments [Member] | Homebuilding Mid East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	3,212	1,911	1,473
Operating Segments [Member] | Homebuilding South East [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,715	1,008	808
Operating Segments [Member] | Mortgage Banking [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	1,089	669	397
Consolidation adjustments and other [Member] | Unallocated Corporate Overhead [Member]
Segment Reporting Other Significant Reconciling Item [Line Items]
Consolidated depreciation and amortization	$ 3,901	$ 4,166	$ 905