Financial Information of Registrant (Parent Company) (Detail 2) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss	$ (10,429,000)	$ 1,998,000	$ (903,000)	$ 730,000	$ (3,545,000)	$ (333,000)	$ (19,899,000)	$ (5,505,000)	$ (8,604,000)	$ (29,282,000)	$ (1,930,000)
Equity in (income) loss of subsidiaries, net of tax									(440,000)	(427,000)	(396,000)
Stock-based compensation									299,000	207,000	144,000
Deferred income taxes									14,883,000	(16,176,000)	(917,000)
Other									155,000	108,000	261,000
Net cash provided by (used in) operating activities									9,001,000	(13,628,000)	29,307,000
Cash flows from investing activities:
Dividends from subsidiary									0
Net cash (used in) provided by investing activities									(12,281,000)	16,654,000	(46,240,000)
Cash flows from financing activities:
Proceeds from term loan from principal stockholder											30,000,000
Net proceeds from issuance of common stock									76,000	68,000	91,000
Net cash provided by financing activities									76,000	68,000	30,091,000
Parent Company
Cash flows from operating activities:
Net loss									(8,604,000)	(29,282,000)	(1,930,000)
Equity in (income) loss of subsidiaries, net of tax									(3,390,000)	27,428,000	441,000
Stock-based compensation									299,000	207,000	144,000
Deferred income taxes									10,945,000	(17,179,000)	(684,000)
Other									71,000	95,000	(203,000)
Change in assets and liabilities									(1,394,000)	17,300,000	2,385,000
Net cash provided by (used in) operating activities									(2,073,000)	(1,431,000)	153,000
Cash flows from investing activities:
Dividends from subsidiary									850,000	1,225,000	2,025,000
Loan to wholly-owned subsidiary									4,000,000	6,400,000	(30,010,000)
Investments in subsidiaries									(4,000,000)	(10,900,000)	(10,000,000)
Net cash (used in) provided by investing activities									850,000	(3,275,000)	(37,985,000)
Cash flows from financing activities:
Proceeds from term loan from principal stockholder											30,000,000
Net proceeds from issuance of common stock									76,000	68,000	91,000
Net cash provided by financing activities									76,000	68,000	30,091,000
Net change in cash and cash equivalents									(1,147,000)	(4,638,000)	(7,741,000)
Cash and cash equivalents, beginning of period				$ 3,457,000				$ 8,095,000	3,457,000	8,095,000	15,836,000
Cash and cash equivalents, end of period	$ 2,310,000				$ 3,457,000				$ 2,310,000	$ 3,457,000	$ 8,095,000