Shareholders' Equity (Tables)

6 Months Ended

Jun. 30, 2017

Stockholders' Equity Note [Abstract]

Accumulated Other Comprehensive Income (Loss) [Table Text Block]

A rollforward of the components of accumulated other comprehensive income (loss) is included as follows (in thousands):

	Unrealized Gain (Loss) on
	Available for Sale Securities			Investment Securities Transferred from AFS			Employee Benefit Plans			Total
Balance, Dec. 31, 2015	$	23,284		$	68		$	(1,765	)	$	21,587
Net change in unrealized gain (loss)	166,566			—			—			166,566
Reclassification adjustments included in earnings:
Interest revenue, Investment securities, Taxable securities	—			(112		)	—			(112		)
Gain on available for sale securities, net	(9,290		)	—			—			(9,290		)
Other comprehensive income (loss), before income taxes	157,276			(112		)	—			157,164
Federal and state income taxes1	61,163			(44		)	—			61,119
Other comprehensive income (loss), net of income taxes	96,113			(68		)	—			96,045
Balance, June 30, 2016	$	119,397		$	—		$	(1,765	)	$	117,632
Balance, Dec. 31, 2016	$	(9,087	)	$	—		$	(1,880	)	$	(10,967	)
Net change in unrealized gain (loss)	33,369			—			—			33,369
Reclassification adjustments included in earnings:
Gain on available for sale securities, net	(2,429		)	—			—			(2,429		)
Other comprehensive income, before income taxes	30,940			—			—			30,940
Federal and state income taxes1	12,009						—			12,009
Other comprehensive income, net of income taxes	18,931			—			—			18,931
Balance, June 30, 2017	$	9,844		$	—		$	(1,880	)	$	7,964

¹  Calculated using a 39 percent effective tax rate.