Financial Information of Registrant (Parent Company) (Detail 2) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ 287,000	$ (3,018,000)	$ 315,000	$ 486,000	$ 21,968,000	$ 2,120,000	$ 3,469,000	$ 511,000	$ (1,930,000)	$ 28,068,000	$ 9,180,000
Equity in (income) loss of subsidiaries, net of tax									(396,000)	(85,000)	(399,000)
Stock-based compensation									144,000	185,000	243,000
Deferred income taxes									(917,000)	(19,223,000)	(1,000)
Other									261,000	224,000	279,000
Net cash provided by operating activities									29,307,000	27,009,000	17,755,000
Cash flows from investing activities:
Dividends from subsidiary									0
Net cash (used in) provided by investing activities									(46,240,000)	3,313,000	(4,877,000)
Cash flows from financing activities:
Proceeds from term loan from principal stockholder									30,000,000
Net proceeds from issuance of common stock									91,000	74,000	51,000
Net cash provided by financing activities									30,091,000	74,000	51,000
Net change in cash and cash equivalents									13,158,000	30,396,000	12,929,000
Cash and cash equivalents, beginning of period				102,429,000				72,033,000	102,429,000	72,033,000	59,104,000
Cash and cash equivalents, end of period	115,587,000				102,429,000				115,587,000	102,429,000	72,033,000
Parent Company
Cash flows from operating activities:
Net income (loss)									(1,930,000)	28,068,000	9,180,000
Equity in (income) loss of subsidiaries, net of tax									441,000	(23,804,000)	(11,657,000)
Stock-based compensation									144,000	185,000	243,000
Deferred income taxes									(684,000)	(7,871,000)	(2,000)
Other									(203,000)	28,000	(6,000)
Change in assets and liabilities									2,385,000	3,197,000	790,000
Net cash provided by operating activities									153,000	(197,000)	(1,452,000)
Cash flows from investing activities:
Dividends from subsidiary									2,025,000	7,425,000	6,635,000
Loan to wholly-owned subsidiary									(30,010,000)
Investments in subsidiaries									(10,000,000)	(44,000)
Net cash (used in) provided by investing activities									(37,985,000)	7,381,000	6,635,000
Cash flows from financing activities:
Proceeds from term loan from principal stockholder									30,000,000
Net proceeds from issuance of common stock									91,000	74,000	51,000
Net cash provided by financing activities									30,091,000	74,000	51,000
Net change in cash and cash equivalents									(7,741,000)	7,258,000	5,234,000
Cash and cash equivalents, beginning of period				$ 15,836,000				$ 8,578,000	15,836,000	8,578,000	3,344,000
Cash and cash equivalents, end of period	$ 8,095,000				$ 15,836,000				$ 8,095,000	$ 15,836,000	$ 8,578,000