Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Reclassification to retained earnings from Tax Act		$ (2,500)
Amounts Before Taxes
Net unrealized holding gains (losses) arising during the period, Before Tax	$ (71,921)	12,752	$ 19,417
Unrealized liquidity losses, Before Tax	3	300	57
Reclassification adjustment for net gains included in net earnings, Before Tax	(3,441)	(5,236)	(3,315)
Amortization of net unrealized gains (losses) and related to transferred securities, Before Tax	0	0	0
Net unrealized gains (losses) on securities, Before Tax	(75,359)	7,816	16,159
Foreign currency translation adjustments, Before Tax	1,714	(14)	(251)
Pension liability adjustment, Before Tax	14,301	(5,958)	(178)
Other comprehensive income, Before Tax	(59,344)	1,844	15,730
Tax (Expense) Benefit
Net unrealized holding gains (losses) arising during the period, Tax	15,103	(4,464)	(6,796)
Unrealized liquidity losses, Tax	(1)	(105)	(20)
Reclassification adjustment for net gains included in net earnings, Tax	723	1,833	1,160
Amortization of net unrealized gains (losses) and related to transferred securities, Tax	0	0	0
Net unrealized gains (losses) on securities, Tax	15,825	(2,736)	(5,656)
Foreign currency translation adjustments, Tax	(360)	5	87
Pension liability adjustment, Tax	(3,003)	2,085	62
Other comprehensive income, Tax	12,462	(646)	(5,507)
Amount Net of Taxes
Net unrealized holding gains (losses) arising during the period, Net of Tax	(56,818)	8,288	12,621
Unrealized liquidity losses, Net of Tax	2	195	37
Reclassification adjustment for net gains included in net earnings, Net of Tax	(2,718)	(3,403)	(2,155)
Amortization of net unrealized gains (losses) and related to transferred securities, Net of Tax	0	0	0
Net unrealized gains (losses) on securities	(59,534)	5,080	10,503
Foreign currency translation adjustments, Net of Tax	1,354	(9)	(164)
Pension liability adjustment, Net of Tax	11,298	(3,873)	(116)
Other comprehensive income (loss)	(46,882)	1,198	10,223
Deferred costs	$ 63,816	$ (5,670)	$ (21,105)