UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - 9 months ended Sep. 30, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Shares Held Under Employee Participation Plan	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Earnings
Balance at beginning of period at Dec. 31, 2016	$ 1,084,241	$ 573	$ (469)	$ 725,670	$ (214,326)	$ 572,793
Balance beginning of period (in shares) at Dec. 31, 2016		57,298
Increase (Decrease) in Stockholders' Equity
Net income (loss)	16,545					16,545
Other comprehensive income	44,858				44,858
Stock-based compensation	9,212			9,212
Issuance of restricted shares, net of shares remitted	(2,321)	$ 1		(2,322)
Issuance of restricted shares, net of shares remitted (in shares)		100
Shares held under employee participation plan	0	$ 0	469	(469)
Shares held under employee participation plan (in shares)		(25)
Repurchases of common stock	$ (24,465)	$ (5)		(24,460)
Repurchases of common stock (in shares)	(500)	(448)
Exercise of stock options	$ 46			46
Exercise of stock options (in shares)		2
Balance at end of period at Sep. 30, 2017	1,128,347	$ 569	$ 0	708,358	$ (169,468)	588,888
Balance ending of period (in shares) at Sep. 30, 2017		56,927
Increase (Decrease) in Stockholders' Equity
Cumulative effect of change in accounting for stock based compensation	$ 231			$ 681		$ (450)