Condensed Consolidated Statements of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at June 30, 2019 at Dec. 31, 2017	$ 505,808	$ 255,836	$ 255,200	$ (5,228)
Balance at June 30, 2019 (in shares) at Dec. 31, 2017		22,955,963
Net Income (Loss) Attributable to Parent	45,109		45,109
Adoption ASU | ASU 2016-01			(62)	62
Adoption ASU | ASU 2018-02			1,093	(1,093)
Other comprehensive income (loss)	(20,700)			(20,700)
Stock option vesting	75	$ 75
Stock options exercised	475	$ 475
Stock options exercised (in shares)		27,400
RSU vesting	1,019	$ 1,019
PSU vesting	0	$ 0
RSUs released (in shares)		58,028
PSUs released (in shares)		0
Repurchase of common stock	(1,124)	$ (323)	(801)
Repurchase of common stock (in shares)		(28,850)
Dividends paid	(12,984)		(12,984)
Balance at September 30, 2019 at Sep. 30, 2018	802,115	$ 541,519	$ 287,555	(26,959)
Balance at September 30, 2019 (in shares) at Sep. 30, 2018		30,417,818
Common Stock, Dividends, Per Share, Cash Paid			$ 0.51
Balance at June 30, 2019 at Jun. 30, 2018	512,344	$ 256,590	$ 276,877	(21,123)
Balance at June 30, 2019 (in shares) at Jun. 30, 2018		23,004,153
Net Income (Loss) Attributable to Parent	16,170		16,170
Other comprehensive income (loss)	(5,836)			(5,836)
Stock option vesting	21	$ 21
Stock options exercised	252	$ 252
Stock options exercised (in shares)		12,900
RSU vesting	274	$ 274
PSU vesting	77	$ 77
RSUs released (in shares)		7,118
PSUs released (in shares)		0
Issuance of common stock (in shares)		7,405,277
Issuance of common stock	284,437	$ 284,437
Repurchase of common stock	(453)	$ (132)	(321)
Repurchase of common stock (in shares)		(11,630)
Dividends paid	(5,171)		(5,171)
Balance at September 30, 2019 at Sep. 30, 2018	802,115	$ 541,519	$ 287,555	(26,959)
Balance at September 30, 2019 (in shares) at Sep. 30, 2018		30,417,818
Common Stock, Dividends, Per Share, Cash Paid			$ 0.17
Balance at June 30, 2019 at Dec. 31, 2018	$ 827,373	$ 541,762	$ 303,490	(17,879)
Balance at June 30, 2019 (in shares) at Dec. 31, 2018	30,417,223	30,417,223
Net Income (Loss) Attributable to Parent	$ 69,182		69,182
Other comprehensive income (loss)	19,378			19,378
Stock option vesting	0
Stock options exercised	$ 2,646	$ 2,646
Stock options exercised (in shares)	166,000	166,000
RSU vesting	$ 863	$ 863
PSU vesting	350	$ 350
RSUs released (in shares)		30,461
RSUs released	0
PSUs released (in shares)		22,237
PSUs released	0
Repurchase of common stock	(4,842)	$ (2,206)	(2,636)
Repurchase of common stock (in shares)		(123,734)
Dividends paid	(18,285)		(18,285)
Balance at September 30, 2019 at Sep. 30, 2019	$ 896,665	$ 543,415	$ 351,751	1,499
Balance at September 30, 2019 (in shares) at Sep. 30, 2019	30,512,187	30,512,187
Common Stock, Dividends, Per Share, Cash Paid			$ 0.60
Balance at June 30, 2019 at Jun. 30, 2019	$ 875,886	$ 542,939	$ 335,145	(2,198)
Balance at June 30, 2019 (in shares) at Jun. 30, 2019		30,502,757
Net Income (Loss) Attributable to Parent	23,395		23,395
Other comprehensive income (loss)	3,697			3,697
Stock option vesting	0
Stock options exercised	146	$ 146
Stock options exercised (in shares)		9,000
RSU vesting	296	$ 296
PSU vesting	102	$ 102
RSUs released (in shares)		4,250
RSUs released	0
PSUs released (in shares)		0
PSUs released	0
Repurchase of common stock	(147)	$ (68)	(79)
Repurchase of common stock (in shares)		(3,820)
Dividends paid	(6,710)		(6,710)
Balance at September 30, 2019 at Sep. 30, 2019	$ 896,665	$ 543,415	$ 351,751	$ 1,499
Balance at September 30, 2019 (in shares) at Sep. 30, 2019	30,512,187	30,512,187
Common Stock, Dividends, Per Share, Cash Paid			$ 0.22