Parent Company Condensed Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 11, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES
Net Income		$ 98,234	$ 105,334	$ 72,968
Net Cash Provided by Operating Activities		138,423	128,017	114,236
INVESTING ACTIVITIES
Net Cash Used in Investing Activities		(210,556)	(201,964)	(212,415)
FINANCING ACTIVITIES
Sale of treasury shares, net		(915)	(657)	(689)
Purchase of treasury shares		(18,222)	(12,256)	0
Cash dividends paid to common shareholders		(37,360)	(34,539)	(28,569)
Payment to repurchase of warrant	$ (7,700)	0	(7,652)	0
Net Cash Provided by Financing Activities		114,467	112,284	75,845
Net increase (decrease) in cash and cash equivalents		42,334	38,337	(22,334)
Cash and cash equivalents at beginning of year		155,489	117,152	139,486
Cash and Cash Equivalents at End of Year		197,823	155,489	117,152
Parent Company
OPERATING ACTIVITIES
Net Income		98,234	105,334	72,968
Equity in undistributed (earnings) losses of subsidiaries		(43,164)	(64,366)	(39,937)
Other		(99)	1,695	480
Net Cash Provided by Operating Activities		54,971	42,663	33,511
INVESTING ACTIVITIES
Net investments in subsidiaries		176	0	0
Acquisitions		(10)	0	0
Net Cash Used in Investing Activities		166	0	0
FINANCING ACTIVITIES
Sale of treasury shares, net		(915)	(657)	(689)
Purchase of treasury shares		(18,222)	(12,256)	0
Cash dividends paid to common shareholders		(37,360)	(34,539)	(28,569)
Payment to repurchase of warrant		0	(7,652)	0
Net Cash Provided by Financing Activities		(56,497)	(55,104)	(29,258)
Net increase (decrease) in cash and cash equivalents		(1,360)	(12,441)	4,253
Cash and cash equivalents at beginning of year		8,869	21,310	17,057
Cash and Cash Equivalents at End of Year		$ 7,509	$ 8,869	$ 21,310