Fair Value Measurements - (Tables of Financial Instruments Measured At Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 1,050,926	$ 1,159,593
Total liabilities at fair value	28,211	8,315
Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	419	419
Municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	5,192	306
Mortgage-Backed Securities (MBS) [Member] | Residential Mortgage Pass-Through Securities Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	274,242	310,978
Mortgage-Backed Securities (MBS) [Member] | Other Residential MBS Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	766,194	845,543
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1,049,787	1,158,868
Total liabilities at fair value	28,033	8,315
Level 2 [Member] | Municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	4,886
Level 2 [Member] | Mortgage-Backed Securities (MBS) [Member] | Residential Mortgage Pass-Through Securities Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	274,242	310,978
Level 2 [Member] | Mortgage-Backed Securities (MBS) [Member] | Other Residential MBS Issued or Guaranteed by U.S. Government Agencies or Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	766,194	845,543
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1,139	725
Total liabilities at fair value	178
Level 3 [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	419	419
Level 3 [Member] | Municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	306	306
Interest rate swap derivatives [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	4,465	2,347
Total liabilities at fair value	28,033	8,315
Interest rate swap derivatives [Member] | Level 2 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	4,465	2,347
Total liabilities at fair value	28,033	$ 8,315
Mortgage banking derivatives | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	414
Total liabilities at fair value	178
Mortgage banking derivatives | Level 3 [Member] | Derivative [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	414
Total liabilities at fair value	$ 178