Allowance for Loan Losses - (Summary of Company's Allowance for Loan Losses ("All") and Recorded Investment in Loans) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 30,850	$ 37,166	$ 29,174	$ 27,119
Provision (recoupment) for loan losses			5,820	17,076
Ending balance	34,959	40,106	34,959	40,106
Carrying amount of loan investments					$ 3,087,945	$ 2,860,921	$ 2,738,504
Loans	30,850	37,166	29,174	27,119	34,959	29,174	40,106
Total Loans					3,087,945	2,860,921	2,738,504
Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		169,282		169,282
Loans		169,282		169,282			169,282
Non ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	30,630	36,951	28,949	26,042
Charge-offs	(121)	(3,686)	(331)	(4,345)
Recoveries	205	210	296	297
Provision (recoupment) for loan losses	4,103	6,400	5,903	17,881
Ending balance	34,817	39,875	34,817	39,875
Ending allowance balance individually evaluated for impairment					39,379		14,977
Ending allowance balance collectively evaluated for impairment							2,523,506
Loans individually evaluated for impairment							231
Loans collectively evaluated for impairment							40,106
Carrying amount of loan investments					2,953,518	2,715,069
Loans	30,630	36,951	28,949	26,042	34,817	28,949	39,875
Total Loans					2,953,518	2,715,069
Non ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending allowance balance individually evaluated for impairment					6,244
Ending allowance balance collectively evaluated for impairment					28,573
Loans collectively evaluated for impairment					2,914,139
Carrying amount of loan investments					134,427
Total Loans					134,427
ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	220	215	225	1,077
Charge-offs		(41)		(41)
Provision (recoupment) for loan losses	(78)	57	(83)	(805)
Ending balance	142	231	142	231
Loans individually evaluated for impairment					142
Carrying amount of loan investments					134,427	145,852
Loans	220	215	225	1,077	142	225	231
Total Loans					134,427	145,852
ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		24,898		24,898
Carrying amount of loan investments							45,716
Loans		24,898		24,898			24,898
Total Loans							45,716
Commercial Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	20,539	28,684	18,821	17,261
Ending balance	24,656	29,982	24,656	29,982
Carrying amount of loan investments					1,775,454		1,490,749
Loans	20,539	28,684	18,821	17,261	24,656	18,821	29,982
Total Loans					1,775,454		1,490,749
Commercial Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		46,875		46,875
Loans		46,875		46,875			46,875
Commercial Portfolio Segment [Member] | Non ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	20,539	28,610	18,821	16,473
Charge-offs		(3,375)	(20)	(3,484)
Recoveries	30	12	41	24
Provision (recoupment) for loan losses	4,087	4,733	5,814	16,967
Ending balance	24,656	29,980	24,656	29,980
Ending allowance balance individually evaluated for impairment					30,458		14,933
Ending allowance balance collectively evaluated for impairment							1,406,609
Loans individually evaluated for impairment							2
Loans collectively evaluated for impairment							29,982
Loans	20,539	28,610	18,821	16,473	24,656	18,821	29,980
Commercial Portfolio Segment [Member] | Non ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending allowance balance individually evaluated for impairment					6,197
Ending allowance balance collectively evaluated for impairment					18,459
Loans collectively evaluated for impairment					1,709,018
Carrying amount of loan investments					35,978
Total Loans					35,978
Commercial Portfolio Segment [Member] | ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		74		788
Provision (recoupment) for loan losses		(72)		(786)
Ending balance		2		2
Loans		74		788			2
Commercial Portfolio Segment [Member] | ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		15,047		15,047
Carrying amount of loan investments							37,265
Loans		15,047		15,047			15,047
Total Loans							37,265
Residential Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,216	4,325	4,387	5,281
Ending balance	4,067	4,504	4,067	4,504
Carrying amount of loan investments					728,511		694,171
Loans	4,216	4,325	4,387	5,281	4,067	4,387	4,504
Total Loans					728,511		694,171
Residential Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		19,341		19,341
Loans		19,341		19,341			19,341
Residential Portfolio Segment [Member] | Non ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,216	4,289	4,387	5,245
Charge-offs	(2)	(140)	(10)	(197)
Recoveries	110	16	113	23
Provision (recoupment) for loan losses	(257)	339	(423)	(567)
Ending balance	4,067	4,504	4,067	4,504
Ending allowance balance individually evaluated for impairment					8,205		39
Ending allowance balance collectively evaluated for impairment							667,461
Loans collectively evaluated for impairment							4,504
Loans	4,216	4,289	4,387	5,245	4,067	4,387	4,504
Residential Portfolio Segment [Member] | Non ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending allowance balance individually evaluated for impairment					45
Ending allowance balance collectively evaluated for impairment					4,022
Loans collectively evaluated for impairment					706,294
Carrying amount of loan investments					14,012
Total Loans					14,012
Residential Portfolio Segment [Member] | ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		36		36
Provision (recoupment) for loan losses		(36)		(36)
Loans		36		36
Residential Portfolio Segment [Member] | ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		4,465		4,465
Carrying amount of loan investments							7,369
Loans		4,465		4,465			4,465
Total Loans							7,369
Consumer Loan [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	280	296	324	411
Ending balance	302	252	302	252
Carrying amount of loan investments					26,960		27,845
Loans	280	296	324	411	302	324	252
Total Loans					26,960		27,845
Consumer Loan [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		1,347		1,347
Loans		1,347		1,347			1,347
Consumer Loan [Member] | Non ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	276	249	319	385
Charge-offs	(119)	(171)	(301)	(388)
Recoveries	55	126	122	185
Provision (recoupment) for loan losses	82	30	154	52
Ending balance	294	234	294	234
Ending allowance balance individually evaluated for impairment					165		2
Ending allowance balance collectively evaluated for impairment							26,258
Loans individually evaluated for impairment							18
Loans collectively evaluated for impairment							252
Loans	276	249	319	385	294	319	234
Consumer Loan [Member] | Non ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending allowance balance individually evaluated for impairment					1
Ending allowance balance collectively evaluated for impairment					293
Loans collectively evaluated for impairment					26,143
Carrying amount of loan investments					652
Total Loans					652
Consumer Loan [Member] | ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4	47	5	26
Provision (recoupment) for loan losses	4	(29)	3	(8)
Ending balance	8	18	8	18
Loans individually evaluated for impairment					8
Loans	4	47	5	26	8	5	18
Consumer Loan [Member] | ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		232		232
Carrying amount of loan investments							240
Loans		232		232			232
Total Loans							240
Commercial Real Estate Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,815	3,861	5,642	4,166
Ending balance	5,934	5,368	5,934	5,368
Carrying amount of loan investments					557,020		525,739
Loans	5,815	3,861	5,642	4,166	5,934	5,642	5,368
Total Loans					557,020		525,739
Commercial Real Estate Portfolio Segment [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		101,719		101,719
Loans		101,719		101,719			101,719
Commercial Real Estate Portfolio Segment [Member] | Non ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,599	3,803	5,422	3,939
Charge-offs				(276)
Recoveries	10	56	20	65
Provision (recoupment) for loan losses	191	1,298	358	1,429
Ending balance	5,800	5,157	5,800	5,157
Ending allowance balance individually evaluated for impairment					551		3
Ending allowance balance collectively evaluated for impairment							423,178
Loans individually evaluated for impairment							211
Loans collectively evaluated for impairment							5,368
Loans	5,599	3,803	5,422	3,939	5,800	5,422	5,157
Commercial Real Estate Portfolio Segment [Member] | Non ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending allowance balance individually evaluated for impairment					1
Ending allowance balance collectively evaluated for impairment					5,799
Loans collectively evaluated for impairment					472,684
Carrying amount of loan investments					83,785
Total Loans					83,785
Commercial Real Estate Portfolio Segment [Member] | ASC 310-30 [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	216	58	220	227
Charge-offs		(41)		(41)
Provision (recoupment) for loan losses	(82)	194	(86)	25
Ending balance	134	211	134	211
Loans individually evaluated for impairment					134
Loans	$ 216	58	$ 220	227	$ 134	$ 220	211
Commercial Real Estate Portfolio Segment [Member] | ASC 310-30 [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Ending balance		5,154		5,154
Carrying amount of loan investments							842
Loans		$ 5,154		$ 5,154			5,154
Total Loans							$ 842