Condensed Consolidated Statements of Shareholders' Equity (unaudited) $ in Thousands	USD ($)
Balance at beginning of period at Dec. 31, 2015	$ 251,092
Balance at beginning of period, as adjusted at Dec. 31, 2015	252,339
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,911
Cash dividends declared	(5,149)
Issuance of common stock	61
Share based compensation	1,200
Share based compensation withholding obligation	(627)
Repurchase of common stock	(16,854)
Net change in accumulated other comprehensive loss, net of related tax effect	3,021
Balance at end of period at Sep. 30, 2016	250,902
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,373
Net change in accumulated other comprehensive loss, net of related tax effect	268
Balance at end of period at Sep. 30, 2016	250,902
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting	1,247
Balance at beginning of period at Dec. 31, 2016	248,980
Balance at beginning of period, as adjusted at Dec. 31, 2016	249,332
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18,764
Cash dividends declared	(6,400)
Issuance of common stock	57
Share based compensation	1,342
Share based compensation withholding obligation	(536)
Repurchase of common stock	0
Net change in accumulated other comprehensive loss, net of related tax effect	5,151
Balance at end of period at Sep. 30, 2017	267,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,859
Net change in accumulated other comprehensive loss, net of related tax effect	155
Balance at end of period at Sep. 30, 2017	267,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting	$ 352