CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - 9 months ended Sep. 30, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings
Beginning balance (in shares) (Previously reported) at Dec. 31, 2016		65,982
Beginning balance (in shares) at Dec. 31, 2016	65,982	65,982
Beginning balance (Previously reported) at Dec. 31, 2016	$ 133,903	$ 7	$ 106,669	$ 27,227
Beginning balance (Cumulative effect of adoption of new accounting standard)	0		409	(409)
Beginning balance at Dec. 31, 2016	133,903	$ 7	107,078	26,818
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	40,774			40,774
Restricted stock vestings (in shares)		324
Restricted stock vestings	107		107
Dividends declared	(16,043)			(16,043)
Dividend equivalents on performance-based restricted stock awards	(82)			(82)
Dividend equivalents cancelled upon forfeiture of restricted stock to satisfy tax withholdings	31			31
Shares issuable in lieu of dividend payments on unvested performance-based restricted stock awards	(56)		(56)
Shares surrendered and cancelled upon vesting of restricted stock to satisfy tax withholdings (in shares)		(125)
Shares surrendered and cancelled upon vesting of restricted stock to satisfy tax withholdings	(2,651)		(2,651)
Stock-based compensation	4,295		4,295
Issuance of common stock under employee stock purchase plan (in shares)		87
Issuance of common stock under employee stock purchase plan	$ 1,330		1,330
Ending balance (in shares) at Sep. 30, 2017	66,268	66,268
Ending balance at Sep. 30, 2017	$ 161,608	$ 7	$ 110,103	$ 51,498